IV. ACIDS AND ALKALIES (part 1 of 2)

IV. ACIDS AND ALKALIES (part 1 of 2)

SULPHURIC ACID--HYDROCHLORIC ACID--NITRIC ACID--ACETIC ACID--AMMONIA--POTASH--SODA--NEUTRAL SODIUM, POTASSIUM, AND AMMONIUM SALTS.

I.--Sulphuric Acid.

§ 51. Sulphuric acid (hydric sulphate, oil of vitriol, H₂SO₄) occurs in commerce in varying degrees of strength or dilution; the strong sulphuric acid of the manufacturer, containing 100 per cent. of real acid (H₂SO₄), has a specific gravity of 1·850. The ordinary brown acid of commerce, coloured by organic matter and holding in solution metallic impurities, chiefly lead and arsenic, has a specific gravity of about 1·750; and contains 67·95 of anhydrous SO₃ = 85·42 of hydric sulphate.

There are also weaker acids used in commerce, particularly in manufactories in which sulphuric acid is made, for special purposes without rectification. The British Pharmacopœia sulphuric acid is directed to be of 1·843 specific gravity, which corresponds to 78·6 per cent. sulphuric anhydride, or 98·8 per cent. of hydric sulphate. The dilute sulphuric acid of the pharmacopœia should have a specific gravity of 1·094, and is usually said to correspond to 10·14 per cent. of anhydrous sulphuric acid; but, if Ure’s Tables are correct, such equals 11·37 per cent.

The general characters of sulphuric acid are as follows:--When pure, it is a colourless, or, when impure, a dark brown to black, oily liquid, without odour at common temperatures, of an exceedingly acid taste, charring most organic tissues rapidly, and, if mixed with water, evolving much heat. If 4 parts of the strong acid are mixed with 1 part of water at 0°, the mixture rises to a heat of 100°; a still greater heat is evolved by mixing 75 parts of acid with 27 of water.

Sulphuric acid is powerfully hygroscopic--3 parts will, in an ordinary atmosphere, increase to nearly 4 in twenty-four hours; in common with all acids, it reddens litmus, yellows cochineal, and changes all vegetable colours. There is another form of sulphuric acid, extensively used in the arts, known under the name of “Nordhausen sulphuric acid,” “fuming acid,” formula H₂S₂O₄. This acid is produced by the distillation of dry ferrous sulphate, at a nearly white heat--either in earthenware or in green glass retorts; the distillate is received in sulphuric acid. As thus manufactured, it is a dark fuming liquid of 1·9 specific gravity, and boiling at 53°. When artificially cooled down to 0°, the acid gradually deposits crystals, which consist of a definite compound of 2 atoms of anhydrous sulphuric acid and 1 atom of water. There is some doubt as to the molecular composition of Nordhausen acid; it is usually considered as hydric sulphate saturated with sulphur dioxide. This acid is manufactured chiefly in Bohemia, and is used, on a large scale, as a solvent for alizarine.

§ 52. =Sulphur Trioxide, or Sulphuric Anhydride= (SO₃), itself may be met with in scientific laboratories, but is not in commerce. Sulphur trioxide forms thin needle-shaped crystals, arranged in feathery groups. Seen in mass, it is white, and has something the appearance of asbestos. It fuses to a liquid at about 18°, boils at 35°, but, after this operation has been performed, the substance assumes an allotropic condition, and then remains solid up to 100°; above 100° it melts, volatilises, and returns to its normal condition. Sulphuric anhydride hisses when it is thrown into water, chemical combination taking place and sulphuric acid being formed. Sulphur trioxide is excessively corrosive and poisonous.

Besides the above forms of acid, there is an officinal preparation called “Aromatic Sulphuric Acid,” made by digesting sulphuric acid, rectified spirit, ginger, and cinnamon together. It contains 10·19 per cent. of SO₃, alcohol, and principles extracted from cinnamon and ginger.

§ 53. Sulphuric acid, in the free state, may not unfrequently be found in nature. The author has had under examination an effluent water from a Devonshire mine, which contained more than one grain of free sulphuric acid per gallon, and was accused, with justice, of destroying the fish in a river. It also exists in large quantities in volcanic springs. In a torrent flowing from the volcano of Parcé, in the Andes, Boussingault calculated that 15,000 tons of sulphuric acid and 11,000 tons of hydrochloric acid were yearly carried down. In the animal and vegetable kingdom, sulphuric acid exists, as a rule, in combination with bases, but there is an exception in the saliva of the Dolium galea, a Sicilian mollusc.

§ 54. =Statistics.=--When something like 900,000 tons of sulphuric acid are produced annually in England alone, and when it is considered that sulphuric acid is used in the manufacture of most other acids, in the alkali trade, in the manufacture of indigo, in the soap trade, in the manufacture of artificial manure, and in a number of technical processes, there is no cause for surprise that it should be the annual cause of many deaths.

The number of deaths from sulphuric acid will vary, other things being equal, in each country, according to the manufactures in that country employing sulphuric acid. The number of cases of poisoning in England and Wales for ten years is given in the following table:--

DEATHS FROM SULPHURIC ACID IN ENGLAND AND WALES FOR THE TEN YEARS ENDING 1892.

ACCIDENT OR NEGLIGENCE.

Ages, 1-5 5-15 15-25 25-65 65 & Total upwards Males, 11 4 2 14 2 33 Females, 4 ... 2 3 ... 9 --------------------------------------------- Totals, 15 4 4 17 2 42 ---------------------------------------------

SUICIDE.

Ages, 15-25 25-65 Total Males, 4 25 29 Females, 5 19 24 --------------------------------- Totals 9 44 53 ---------------------------------

During the ten years, no case of murder through sulphuric acid is on record; hence the total deaths, as detailed in the tables, amount to 95, or a little over 9 a year.

Falck,[64] in comparing different countries, considers the past statistics to show that in France sulphuric acid has been the cause of 4·5 to 5·5 per cent. of the total deaths from poison, and in England 5·9 per cent. In England, France, and Denmark, taken together, 10·8, Prussia 10·6; while in certain cities, as Berlin and Vienna, the percentages are much higher--Vienna showing 43·3 per cent., Berlin 90 per cent.

[64] Lehrbuch der praktischen Toxicologie, p. 54.

§ 55. =Accidental, Suicidal, and Criminal Poisoning.=--Deaths from sulphuric acid are, for the most part, accidental, occasionally suicidal, and, still more rarely, criminal. In 53 out of 113 cases collected by Böhm, in which the cause of the poisoning could, with fair accuracy, be ascertained, 45·3 per cent. were due to accident, 30·2 were suicidal, and 24·5 per cent. were cases of criminal poisoning, the victims being children.

The cause of the comparatively rare use of sulphuric acid by the poisoner is obvious. First of all, the acid can never be mixed with food without entirely changing its aspect; next, it is only in cases of insensibility or paralysis that it could be administered to an adult, unless given by force, or under very exceptional circumstances; and lastly, the stains on the mouth and garments would at once betray, even to uneducated persons, the presence of something wrong. As an agent of murder, then, sulphuric acid is confined in its use to young children, more especially to the newly born.

There is a remarkable case related by Haagan,[65] in which an adult man, in full possession of his faculties, neither paralysed nor helpless, was murdered by sulphuric acid. The wife of a day-labourer gave her husband drops of sulphuric acid on sugar, instead of his medicine, and finally finished the work by administering a spoonful of the acid. The spoon was carried well to the back of the throat, so that the man took the acid at a gulp. 11 grms. (171 grains) of sulphuric acid, partly in combination with soda and potash, were separated from his stomach.

[65] Gross: Die Strafrechtspflege in Deutschland, 4, 1861, Heft I. S. 181.

Accidental poisoning is most common among children. The oily, syrupy-looking sulphuric acid, when pure, may be mistaken for glycerin or for syrup; and the dark commercial acid might, by a careless person, be confounded with porter or any dark-looking medicine.

Serious and fatal mistakes have not unfrequently arisen from the use of injections. Deutsch[66] relates how a midwife, in error, administered to mother and child a sulphuric acid clyster; but little of the fluid could in either case have actually reached the rectum, for the mother recovered in eight days, and in a little time the infant was also restored to health. Sulphuric acid has caused death by injections into the vagina. H. C. Lombard[67] observed a case of this kind, in which a woman, aged thirty, injected half a litre of sulphuric acid into the vagina, for the purpose of procuring abortion. The result was not immediately fatal, but the subsequent inflammation and its results so occluded the natural passage that the birth became impossible, and a Cæsarean section extracted a dead child, the mother also dying.

[66] Preuss. Med. Vereins-Zeitung, 1848, No. 13.

[67] Journ. de Chim. Méd., tom. vii., 1831.

An army physician prescribed for a patient an emollient clyster. Since it was late at night, and the apothecary in bed, he prepared it himself; but not finding linseed oil, woke the apothecary, who took a bottle out of one of the recesses and placed it on the table. The bottle contained sulphuric acid; a soldier noticed a peculiar odour and effervescence when the syringe was charged, but this was unheeded by the doctor. The patient immediately after the operation suffered the most acute agony, and died the following day; before his death, the bedclothes were found corroded by the acid, and a portion of the bowel itself came away.[68]

[68] Maschka’s Handbuch, p. 86; Journal de Chimie Médicale, t. i. No. 8, 405, 1835.

§56. =Fatal Dose.=--The amount necessary to kill an adult man is not strictly known; fatality so much depends on the concentration of the acid and the condition of the person, more especially whether the stomach is full or empty, that it will be impossible ever to arrive at an accurate estimate. Christison’s case, in which 3·8 grms. (60 grains) of concentrated acid killed an adult, is the smallest lethal dose on record. Supposing that the man weighed 68½ kilo. (150 lbs.), this would be in the proportion of ·05 grm. per kilo. There is also the case of a child of one year, recorded by Taylor, in which 20 drops caused death. If, however, it were asked in a court of law what dose of concentrated sulphuric acid would be dangerous, the proper answer would be: so small a quantity as from 2 to 3 drops of the strong undiluted acid might cause death, more especially if conveyed to the back of the throat; for if it is improbable that on such a supposition death would be sudden, yet there is a possibility of permanent injury to the gullet, with the result of subsequent contraction, and the usual long and painful malnutrition thereby induced. It may be laid down, therefore, that all quantities, even the smallest, of the strong undiluted acid come under the head of hurtful, noxious, and injurious.

§ 57. =Local Action of Sulphuric Acid.=--The action of the acid on living animal tissues has been studied of late by C. Ph. Falck and L. Vietor.[69] Concentrated acid precipitates albumen, and then redissolves it; fibrin swells and becomes gelatinous; but if the acid is weak (e.g., 4 to 6 per cent.) it is scarcely changed. Muscular fibre is at first coloured amber-yellow, swells to a jelly, and then dissolves to a red-brown turbid fluid. When applied to the mucous membrane of the stomach, the mucous tissue and the muscular layer beneath are coloured white, swell, and become an oily mass.

[69] Deutsche Klinik, 1864, Mo. 1-32, and Vietor’s Inaugur.-Dissert., Marburg, 1803.

When applied to a rabbit’s ear,[70] the parenchyma becomes at first pale grey and semi-transparent at the back of the ear; opposite the drop of acid appear spots like grease or fat drops, which soon coalesce. The epidermis with the hair remains adherent; the blood-vessels are narrowed in calibre, and the blood, first in the veins, and then in the arteries, is coloured green and then black, and fully coagulates. If the drop, with horizontal holding of the ear, is dried in, an inflammatory zone surrounds the burnt spot in which the blood circulates; but there is complete stasis in the part to which the acid has been applied. If the point of the ear is dipped in the acid, the cauterised part rolls inwards; after the lapse of eighteen hours the part is brown and parchment-like, with scattered points of coagulated blood; then there is a slight swelling in the healthy tissues, and a small zone of redness; within fourteen days a bladder-like greenish-yellow scab is formed, the burnt part itself remaining dry. The vessels from the surrounding zone of redness gradually penetrate towards the cauterised spot, the fluid in the bleb becomes absorbed, and the destroyed tissues fall off in the form of a crust.

[70] Samuel, Entzündung u. Brand, in Virchow’s Archiv f. Path. Anat., Bd. 51, Hft. 1 u. 2, S. 41, 1870.

The changes that sulphuric acid cause in blood are as follows: the fibrin is at first coagulated and then dissolved, and the colouring matter becomes of a black colour. These changes do not require the strongest acid, being seen with an acid of 60 per cent.

§ 58. The action of the acid on various non-living matters is as follows: poured on all vegetable earth, there is an effervescence, arising from decomposition of carbonates; any grass or vegetation growing on the spot is blackened and dies; an analysis of the layer of earth, on which the acid is poured, shows an excess of sulphates as compared with a similar layer adjacent; the earth will only have an acid reaction, if there has been more than sufficient acid to neutralise all alkalies and alkaline earths.

Wood almost immediately blackens, and the spot remains moist.

Spots on paper become quickly dark, and sometimes exhibit a play of colours, such as reddish-brown; ultimately the spot becomes very black, and holes may be formed; even when the acid is dilute, the course is very similar, for the acid dries in, until it reaches a sufficient degree of concentration to attack the tissue. I found small drops of sulphuric acid on a brussels carpet, which had a red pattern on a dark green ground with light green flowers, act as follows: the spots on the red at the end of a few hours were of a dark maroon colour, the green was darkened, and the light green browned; at the end of twenty-four hours but little change had taken place, nor could any one have guessed the cause of the spots without a close examination. Spots of the strong acid on thin cotton fabrics rapidly blackened, and actual holes were formed in the course of an hour; the main difference to the naked eye, between the stains of the acid and those produced by a red-hot body, lay in the moistness of the spots. Indeed, the great distinction, without considering chemical evidence, between recent burns of clothing by sulphuric acid and by heat, is that in the one case--that of the acid--the hole or spot is very moist; in the other very dry. It is easy to imagine that this distinction may be of importance in a legal investigation.

Spots of acid on clothing fall too often under the observation of all those engaged in practical chemical work. However quickly a spot of acid is wiped off, unless it is immediately neutralised by ammonia, it ultimately makes a hole in the cloth; the spot, as a rule, whatever the colour of the cloth, is of a blotting-paper red.

Sulphuric acid dropped on iron, attacks it, forming a sulphate, which may be dissolved out by water. If the iron is exposed to the weather the rain may wash away all traces of the acid, save the corrosion; but it would be under those circumstances impossible to say whether the corrosion was due to oxidation or a solvent.

To sum up briefly: the characters of sulphuric acid spots on organic matters generally are black, brown, or red-coloured destructions of tissue, moisture, acid-reaction (often after years), and lastly the chemical evidence of sulphuric acid or sulphates in excess.

=Caution necessary in judging of Spots, &c.=--An important case, related by Maschka, shows the necessity of great caution in interpreting results, unless all the circumstances of a case be carefully collated. A live coal fell on the bed of a weakly infant, five months old. The child screamed, and woke the father, who was dozing by the fire; the man, in terror, poured a large pot of water on the child and burning bed. The child died the following day.

A post-mortem examination showed a burn on the chest of the infant 2 inches in length. The tongue, pharynx, and gullet were all healthy; in the stomach a patch of mucous membrane, about half an inch in extent, was found to be brownish, friable, and very thin. A chemical examination showed that the portion of the bed adjacent to the burnt place contained free sulphuric acid. Here, then, was the following evidence: the sudden death of a helpless infant, a carbonised bed-cover with free sulphuric acid, and, lastly, an appearance in the stomach which, it might be said, was not inconsistent with sulphuric acid poisoning. Yet a careful sifting of the facts convinced the judges that no crime had been committed, and that the child’s death was due to disease. Afterwards, experiment showed that if a live coal fall on to any tissue, and be drenched with water, free sulphuric acid is constantly found in the neighbourhood of the burnt place.

§ 59. =Symptoms.=--The symptoms may be classed in two divisions, viz.:--1. External effects of the acid. 2. Internal effects and symptoms arising from its interior administration.

1. =External Effects.=--Of late years several instances have occurred in which the acid has been used criminally to cause disfiguring burns of the face. The offence has in all these cases been committed by women, who, from motives of revengeful jealousy, have suddenly dashed a quantity of the acid into the face of the object of their resentment. In such cases, the phenomena observed are not widely different from those attending scalds or burns from hot neutral fluids. There is destruction of tissue, not necessarily deep, for the acid is almost immediately wiped off; but if any should reach the eye, inflammation, so acute as to lead to blindness, is the probable consequence. The skin is coloured at first white, at a later period brown, and part of it may be, as it were, dissolved. If the tract or skin touched by the acid is extensive, death may result. The inflammatory processes in the skin are similar to those noticed by Falck and Vietor in their experiments, already detailed (p. 79).

=Internal Effects of Acids generally.=--It may not be out of place, before speaking of the internal effects of sulphuric acid, to make a few remarks upon the action of acids generally. This action differs according to the kind of animal; at all events, there is a great difference between the action of acids on the herb-eating animals and the carnivora; the latter bear large doses of acids well, the former ill. For instance, the rabbit, if given a dose of any acid not sufficient to produce local effects but sufficient to affect its functions, will soon become paralysed and lie in a state of stupor, as if dead; the same dose per kilo. will not affect the dog. The reason for this is that the blood of the dog is able to neutralise the acid by ammonia, and that the blood of the rabbit is destitute of this property. Man is, in this respect, nearer to the dog than to the plant-eaters. Stadelmann has shown that a man is able to ingest large relative doses of oxybutyric acid, to neutralise the acid by ammonia, and to excrete it by means of the kidneys as ammonium butyrate.

Acids, however, if given in doses too great to be neutralised, alike affect plant- and flesh-eaters; death follows in all cases before the blood becomes acid. Salkowsky[71] has, indeed, shown that the effect of lessening the alkalinity of the blood by giving a rabbit food from which it can extract no alkali produces a similar effect to the actual dosing with an acid.

[71] Virchow’s Archiv, Bd. 58, 1.

2. =Internal Effects of Sulphuric Acid.=--When sulphuric acid is taken internally, the acute and immediate symptom is pain. This, however, is not constant, since, in a few recorded cases, no complaint of pain has been made; but these cases are exceptional; as a rule, there will be immediate and great suffering. The tongue swells, the throat is also swollen and inflamed, swallowing of saliva even may be impossible. If the acid has been in contact with the epiglottis and vocal apparatus, there may be spasmodic croup and even fatal spasm of the glottis.

The acid, in its passage down the gullet, attacks energetically the mucous membrane and also the lining of the stomach; but the action does not stop there, for Lesser found in eighteen out of twenty-six cases (69 per cent.) that the corrosive action extended as far as the duodenum. There is excessive vomiting and retching; the matters vomited are acid, bloody, and slimy; great pieces of mucous membrane may be in this way expelled, and the whole of the lining membrane of the gullet may be thrown up entire. The bowels are, as a rule, constipated, but exceptionally there has been diarrhœa; the urine is sometimes retained; it invariably contains an excess of sulphates and often albumen, with hyaline casts of the uriniferous tubes. The pulse is small and frequent, the breathing slow, the skin very cold and covered with sweat; the countenance expresses great anxiety, and the extremities may be affected with cramps or convulsions. Death may take place within from twenty-four to thirty-six hours, and be either preceded by dyspnœa or by convulsions; consciousness is, as a rule, maintained to the end.

There are also more rapid cases than the above; a large dose of sulphuric acid taken on an empty stomach may absolutely dissolve it, and pass into the peritoneum; in such a case there is really no difference in the symptoms between sudden perforation of the stomach from disease, a penetrating wound of the abdomen, and any other sudden fatal lesion of the organs in the abdominal cavity (for in all these instances the symptoms are those of pure collapse); the patient is ashen pale, with pulse quick and weak, and body bathed in cold sweat, and he rapidly dies, it may be without much complaint of local pain.

If the patient live longer than twenty-four hours, the symptoms are mainly those of inflammation of the whole mucous tract, from the mouth to the stomach; and from this inflammation the patient may die in a variable period, of from three to eleven days, after taking the poison. In one case the death occurred suddenly, without any immediately preceding symptoms rendering imminent death probable. If this second stage is passed, then the loss of substance in the gullet and in the stomach almost invariably causes impairment of function, leading to a slow and painful death. The common sequence is stricture of the gullet, combined with feeble digestion, and in a few instances stricture of the pylorus. A curious sequel has been recorded by Mannkopf, viz., obstinate intercostal neuralgia; it has been observed on the fourth, seventh, and twenty-second day.

§ 60. =Treatment of Acute Poisoning by the Mineral Acids.=--The immediate indication is the dilution and neutralisation of the acid. For this purpose, finely-divided chalk, magnesia, or sodic carbonate may be used, dissolved or suspended in much water. The use of the stomach-pump is inadvisable, for the mucous membrane of the gullet may be so corroded by the acid that the passage of the tube down will do injury; unless the neutralisation is immediate, but little good is effected; hence it will often occur that the bystanders, if at all conversant with the matter, will have to use the first thing which comes to hand, such as the plaster of a wall, &c.; and lastly, if even these rough antidotes are not to be had, the best treatment is enormous doses of water, which will dilute the acid and promote vomiting. The treatment of the after-effects belongs to the province of ordinary medicine, and is based upon general principles.

§ 61. =Post-mortem Appearances.=[72]--The general pathological appearances to be found in the stomach and internal organs differ according as the death is rapid or slow; if the death takes place within twenty-four hours, the effects are fairly uniform, the differences being only in degree; while, on the other hand, in those cases which terminate fatally from the more remote effects of the acid, there is some variety. It may be well to select two actual cases as types, the one patient dying from acute poisoning, the other surviving for a time, and then dying from ulceration and contraction of the digestive tract.

[72] It has been observed that putrefaction in cases of death from sulphuric acid is slow. Casper suggests this may be due to the neutralisation of ammonia; more probably it is owing to the antiseptic properties all mineral acids possess.

A hatter, early in the morning, swallowed a large mouthful of strong sulphuric acid, a preparation which he used in his work--(whether the draught was taken accidentally or suicidally was never known). He died within two hours. The whole tongue was sphacelated, parts of the mucous membrane being dissolved; the inner surface of the gullet, as well as the whole throat, was of a grey-black colour; the mucous membrane of the stomach was coal-black, and so softened that it gave way like blotting-paper under the forceps, the contents escaping into the cavity of the abdomen. The peritoneum was also blackened as if burnt; probably there had been perforation of the stomach during life; the mucous membrane of the duodenum was swollen, hardened, and looked as if it had been boiled; while the blood was of a cherry-red colour, and of the consistence of a thin syrup. The rest of the organs were healthy; a chemical research on the fluid which had been collected from the stomach, gullet, and duodenum showed that it contained 87·25 grains of free sulphuric acid.[73]

[73] Casper, vol. ii. case 194.

This is, perhaps, the most extreme case of destruction on record; the cause of the unusually violent action is referable to the acid acting on an empty stomach. It is important to note that even with this extensive destruction of the stomach, life was prolonged for two hours.

The case I have selected to serve as a type of a chronic but fatal illness produced from poisoning by sulphuric acid is one related by Oscar Wyss. A cook, thirty-four years of age, who had suffered many ailments, drank, on the 6th of November 1867, by mistake, at eight o’clock in the morning, two mouthfuls of a mixture of 1 part of sulphuric acid and 4 of water. Pain in the stomach and neck, and vomiting of black masses, were the immediate symptoms, and two hours later he was admitted into the hospital in a state of collapse, with cold extremities, cyanosis of the face, &c. Copious draughts of milk were given, and the patient vomited much, the vomit still consisting of black pultaceous matters, in which, on a microscopical examination, could be readily detected columnar epithelium of the stomach and mucous tissue elements. The urine was of specific gravity 1·033, non-albuminous; on analysis it contained 3·388 grms. of combined sulphuric acid.

On the second day there was some improvement in the symptoms; the urine contained 1·276 grm. of combined sulphuric acid; on the third day 2·665 grms. of combined sulphuric acid; and on the tenth day the patient vomited up a complete cast of the mucous membrane of the gullet. The patient remained in the hospital, and became gradually weaker from stricture of the gullet and impairment of the digestive powers, and died, two months after taking the poison, on the 5th of January 1868.

The stomach was found small, contracted, with many adhesions to the pancreas and liver; it was about 12 centimetres long (4·7 inches), and from 2 to 2·5 centimetres (·7 to ·9 inch) broad, contracted to somewhat the form of a cat’s intestine; there were several transverse rugæ; the walls were thickened at the small curvature, measurements giving 5 mm. (·19 inch) in the middle, and beyond about 2·75 mm. (·11 inch); in the upper two-thirds the lumen was so contracted as scarcely to admit the point of the little finger. The inner surface was covered with a layer of pus, with no trace of mucous tissue, and was everywhere pale red, uneven, and crossed by cicatricial bands. In two parts, at the greater curvature, the mucous surface was strongly injected in a ring-like form, and in the middle of the ring was a deep funnel-shaped ulcer; a part of the rest of the stomach was strongly injected and scattered over with numerous punctiform, small, transparent bladders. The gullet was contracted at the upper part (just below the epiglottis) from 20 to 22 mm. (·78 to ·86 inch) in diameter; it then gradually widened to measure about 12 mm. (·47 inch) at the diaphragm; in the neighbourhood of the last contraction the tissue was scarred, injected, and ulcerated; there were also small abscesses opening into this portion of the gullet.

E. Fraenkel and F. Reiche[74] have studied the effects of sulphuric acid on the kidney. In rapid cases they find a wide-spread coagulation of the epithelium in the convoluted and straight urinary canaliculi, with destruction of the kidney parenchyma, but no inflammation.

[74] Virchow’s Archiv, Bd. 131, f. 130.

§ 62. The museums of the different London hospitals afford excellent material for the study of the effects of sulphuric acid on the pharynx, gullet, and stomach; and it may be a matter of convenience to students if the more typical examples at these different museums be noticed in detail, so that the preparations themselves may be referred to.

In St. Bartholomew’s Museum, No. 1942, is an example of excessive destruction of the stomach by sulphuric acid. The stomach is much contracted, and has a large aperture with ragged edges; the mucous membrane is thickened, charred, and blackened.

No. 1941, in the same museum, is the stomach of a person who died from a large dose of sulphuric acid. When recent, it is described as of a deep red colour, mottled with black; appearances which, from long soaking in spirit, are not true at the present time; but the rough, shaggy state of the mucous tissue can be traced; the gullet and the pylorus appear the least affected.

St. George’s Hospital, ser. ix., 146, 11 and 43, e.--The pharynx and œsophagus of a man who was brought into the hospital in a state of collapse, after a large but unknown dose of sulphuric acid. The lips were much eroded, the mucous membrane of the stomach, pharynx, and œsophagus show an extraordinary shreddy condition; the lining membrane of the stomach is much charred, and the action has extended to the duodenum; the muscular coat is not affected.

Guy’s Hospital, No. 1799.--A preparation showing the mucous membrane of the stomach entirely denuded. The organ looks like a piece of thin paper.

No. 1799²⁰. The stomach of a woman who poisoned herself by drinking a wine-glassful of acid before breakfast. She lived eleven days. The main symptoms were vomiting and purging, but there was no complaint of pain. There is extensive destruction of mucous membrane along the lesser curvature and towards the pyloric extremity; a portion of the mucous membrane is floating as a slough.

No. 1799²⁵ is the gullet and stomach of a man who took about 3 drachms of the strong acid. He lived three days without much apparent suffering, and died unexpectedly. The lining membrane of the œsophagus has the longitudinal wrinkles or furrows so often, nay, almost constantly, met with in poisoning by the acids. The mucous tissue of the stomach is raised in cloudy ridges, and blackened.

No. 1799³⁵ is a wonderfully entire cast of the gullet from a woman who swallowed an ounce of sulphuric acid, and is said, according to the catalogue, to have recovered.

University College.--In this museum will be found an exquisite preparation of the effects of sulphuric acid. The mucous membrane of the œsophagus is divided into small quadrilateral areas by longitudinal and transverse furrows; the stomach is very brown, and covered with shreddy and filamentous tissue; the brown colour is without doubt the remains of extravasated and charred blood.

No. 6201 is a wax cast representing the stomach of a woman who died after taking a large dose of sulphuric acid. A yellow mass was found in the stomach; there are two perforations, and the mucous membrane is entirely destroyed.

§ 63. =Chronic Poisoning by Sulphuric Acid.=--Weiske[75] has experimentally proved that lambs, given for six months small doses of sulphuric acid, grow thin, and their bones, with the exception of the bones of the head and the long bones, are poor in lime salts, the muscles also are poor in the same constituents. Kobert[76] thinks that drunkards on the continent addicted to “Schnaps,” commonly a liquid acidified with sulphuric acid to give it a sharp taste, often show typical chronic sulphuric acid poisoning.

[75] H. Weiske, Journ. f. Landwirthsch., 1887, 417.

[76] Lehrbuch der Intoxicationen, S. 210.

Detection and Estimation of Free Sulphuric Acid.

§ 64. The general method of separating the mineral acids is as follows: the tissues, or matters, are soaked in distilled water for some time. If no free acid is present, the liquid will not redden litmus-paper, or give an acid reaction with any of the numerous tinctorial agents in use by the chemist for the purposes of titration. After sufficient digestion in water, the liquid extract is made up to some definite bulk and allowed to subside. Filtration is unnecessary. A small fractional part (say, for example, should the whole be 250 c.c., 1/100th or 2·5 c.c.) is taken, and using as an indicator cochineal or phenolphthalein, the total acidity is estimated by a decinormal solution of soda. By this preliminary operation, some guide for the conduct of the future more exact operations is obtained. Should the liquid be very acid, a small quantity of the whole is to be now taken, but if the acidity is feeble, a larger quantity is necessary, and sufficient quinine then added to fix the acid--100 parts of sulphuric acid are saturated by 342 parts of quinine monohydrate. Therefore, on the supposition that all the free acid is sulphuric, it will be found sufficient to add 3·5 parts of quinine for every 1 part of acid, estimated as sulphuric, found by the preliminary rough titration; and as it is inconvenient to deal with large quantities of alkaloid, a fractional portion of the liquid extract (representing not more than 50 mgrms. of acid) should be taken, which will require 175 mgrms. of quinine.

On addition of the quinine, the neutralised liquid is evaporated to dryness, or to approaching dryness, and then exhausted by strong alcohol. The alcoholic extract is, after filtration, dried up, and the quinine sulphate, nitrate, or hydrochlorate, as the case may be, filtered off and extracted by boiling water, and precipitated by ammonia, the end result being quinine hydrate (which may be filtered off and used again for similar purposes) and a sulphate, nitrate or chloride of ammonia in solution. It therefore remains to determine the nature and quantity of the acids now combined with ammonia. The solution is made up to a known bulk, and portions tested for chlorides by nitrate of silver, and for nitrates by the copper or the ferrous sulphate test. If sulphuric acid is present, there will be a precipitate of barium sulphate, which, on account of its density and insolubility in nitric or hydrochloric acids, is very characteristic. For estimating the sulphuric acid thus found, it will only be necessary to take a known bulk of the same liquid, heat it to boiling after acidifying by hydrochloric acid, and then add a sufficient quantity of baric chloride solution. Unless this exact process is followed, the analyst is likely to get a liquid which refuses to filter clear, but if the sulphate be precipitated from a hot liquid, it usually settles rapidly to the bottom of the vessel, and the supernatant fluid can be decanted clear; the precipitate is washed by decantation, and ultimately collected on a filter, dried, and weighed.

The sulphate of baryta found, multiplied by ·3434, equals the sulphuric anhydride.

The older process was to dissolve the free sulphuric acid out by alcohol. As is well known, mineral sulphates are insoluble in, and are precipitated by, alcohol, whereas sulphuric acid enters into solution. The most valid objection, as a quantitative process, to the use of alcohol, is the tendency which all mineral acids have to unite with alcohol in organic combination, and thus, as it were, to disappear; and, indeed, results are found, by experiment, to be below the truth when alcohol is used. This objection does not hold good if either merely qualitative evidence, or a fairly approximate quantation, is required. In such a case, the vomited matters, the contents of the stomach, or a watery extract of the tissues, are evaporated to a syrup, and then extracted with strong alcohol and filtered; a little phenolphthalein solution is added, and the acid alcohol exactly neutralised by an alcoholic solution of clear decinormal or normal soda. According to the acidity of the liquid, the amount used of the decinormal or normal soda is noted, and then the whole evaporated to dryness, and finally heated to gentle redness. The alkaline sulphate is next dissolved in very dilute hydrochloric acid, and the solution precipitated by chloride of barium in the usual way. The quantitative results, although low, would, in the great majority of cases, answer the purpose sufficiently.

A test usually enumerated, Hilger’s test for mineral acid, may be mentioned. A liquid, which contains a very minute quantity of mineral acid, becomes of a blue colour (or, if 1 per cent. or above, of a green) on the addition of a solution of methyl aniline violet; but this test, although useful in examining vinegars (see “Foods,” p. 519), is not of much value in toxicology, and the quinine method for this purpose meets every conceivable case, both for qualitative and quantitative purposes.

§ 65. =The Urine.=--Although an excess of sulphates is found constantly in the urine of persons who have taken large doses of sulphuric acid, the latter has never been found in that liquid in a free state, so that it will be useless to search for free acid. It is, therefore, only necessary to add HCl to filter the fluid, and precipitate direct with an excess of chloride of barium. It is better to operate in this manner than to burn the urine to an ash, for in the latter case part of the sulphates, in the presence of phosphates, are decomposed, and, on the other hand, any organic sulphur combinations are liable to be estimated as sulphates.

It may also be well to pass chlorine gas through the same urine which has been treated with chloride of barium, and from which the sulphate has been filtered off. The result of this treatment will be a second precipitate of sulphate derived from sulphur, in a different form of combination than that of sulphate.

The greatest amount of sulphuric acid as mineral and organic sulphate is separated, according to Mannkopf[77] and Schultzen,[78] within five hours after taking sulphuric acid; after three days the secretion, so far as total sulphates is concerned, is normal.

[77] “Toxicologie der Schwefelsäure,” Wiener med. Wochen., 1862, 1863.

[78] Archiv. f. Anatom. u. Physiol., 1864.

The normal amount of sulphuric acid excreted daily, according to Thudichum, is from 1·5 to 2·5 grms., and organic sulphur up to ·2 grm. in the twenty-four hours, but very much more has been excreted by healthy persons.

Lehmann made some observations on himself, and found that, on an animal diet, he excreted no less than 10·399 grms. of sulphuric acid per day, while on mixed food a little over 7 grms.; but, as Thudichum justly observes, this great amount must be referred to individual peculiarity. The amount of sulphates has a decided relation to diet. Animal food, although not containing sulphates, yet, from the oxidation of the sulphur-holding albumen, produces a urine rich in sulphate. Thus Vogel found that a person, whose daily average was 2·02 grms., yielded 7·3 on a meat diet. The internal use of sulphur, sulphides, and sulphates, given in an ordinary medicinal way, is traceable in the urine, increasing the sulphates. In chronic diseases the amount of sulphates is decreased, in acute increased.

Finally, it would appear that the determination of sulphates in the urine is not of much value, save when the normal amount that the individual secretes is primarily known. On the other hand, a low amount of sulphates in the urine of a person poisoned by sulphuric acid has not been observed within three days of the taking of the poison, and one can imagine cases in which such a low result might have forensic importance.

The presence of albumen in the urine has been considered by some a constant result of sulphuric acid poisoning, but although when looked for it is usually found, it cannot be considered constant. O. Smoler,[79] in eighteen cases of various degrees of sulphuric acid poisoning, found nothing abnormal in the urine. Wyss[80] found in the later stages of a case indican and pus. E. Leyden and Ph. Munn[81] always found blood in the urine, as well as albumen, with casts and cellular elements. Mannkopf[82] found albuminuria in three cases out of five; in two of the cases there were fibrinous casts; in two the albumen disappeared at the end of the second or third day, but in one it continued for more than twenty days. Bamberger[83] has observed an increased albuminuria, with separation of the colouring matter of the blood. In this case it was ascribed to the action of the acid on the blood.

[79] Archiv der Heilkunde red. v. E. Wagner, 1869, Hft. 2, S. 181.

[80] Wiener Medicinal-Halle, 1861, Jahr. 6, No. 46.

[81] Virchow’s Archiv f. path. Anat., 1861. Bd. 22, Hft. 3 u. 4, S. 237.

[82] Wien. med. Wochenschrift, 1862, Nro. 35; 1863, Nro. 5.

[83] Wien. Med.-Halle, 1864, Nro. 29, 30.

§ 66. =The Blood.=--In Casper’s case, No. 193, the vena cava of a child, who died within an hour after swallowing a large dose of sulphuric acid, was filled with a cherry-red, strongly acid-reacting blood. Again, Casper’s case, No. 200, is that of a young woman, aged 19, who died from a poisonous dose of sulphuric acid. At the autopsy, four days after death, the following peculiarities of the blood were thus noted:--“The blood had an acid reaction, was dark, and had (as is usual in these cases) a syrupy consistence, while the blood-corpuscles were quite unchanged. The blood was treated with an excess of absolute alcohol, filtered, the filtrate concentrated on a water-bath, the residue exhausted with absolute alcohol, &c. It yielded a small quantity of sulphuric acid.”

Other similar cases might be noted, but it must not for a moment be supposed that the mass of the blood contains any free sulphuric acid during life. The acidity of the blood in the vena cava may be ascribed to post-mortem endosmosis, the acid passing through the walls of the stomach into the large vessel.

§ 67. =Sulphates.=--If the acid swallowed should have been entirely neutralised by antidotes, such as chalk, &c., it becomes of the first importance to ascertain, as far as possible, by means of a microscopical examination, the nature of the food remaining in the stomach, and then to calculate the probable contents in sulphates of the food thus known to be eaten. It will be found that, with ordinary food, and under ordinary circumstances, only small percentages of combined sulphuric acid can be present.

As an example, take the ordinary rations of the soldier, viz.:--12 oz. of meat, 24 oz. of bread, 16 oz. of potatoes, 8 oz. of other vegetables; with sugar, salt, tea, coffee, and water. Now, if the whole quantity of these substances were eaten at a meal, they would not contain more than from 8 to 10 grains (·5 to ·6 grm.) of anhydrous sulphuric acid, in the form of sulphates.

So far as the contents of the stomach are concerned, we have only to do with sulphates introduced in the food, but when once the food passes further along the intestinal canal, circumstances are altered, for we have sulphur-holding secretions, which, with ordinary chemical methods, yield sulphuric acid. Thus, even in the newly-born infant, according to the analyses of Zweifler, the mineral constituents of meconium are especially sulphate of lime, with a smaller quantity of sulphate of potash. The amount of bile which flows into the whole tract of the intestinal canal is estimated at about half a litre in the twenty-four hours; the amount of sulphur found in bile varies from ·89 to 3 per cent., so that in 500 c.c. we might, by oxidising the sulphur, obtain from 2·2 to 7·5 grms. of sulphuric anhydride.

It is therefore certain that large quantities of organic sulphur-compounds may be found in the human intestinal canal, for with individuals who suffer from constipation, the residues of the biliary secretion accumulate for many days. Hence, if the analyst searches for sulphates in excretal matters, all methods involving destruction of organic substances, whether by fire or by fluid-oxidising agents, are wrong in principle, and there is nothing left save to separate soluble sulphates by dialysis, or to precipitate direct out of an aqueous extract.

Again, sulphate of magnesia is a common medicine, and so is sodic sulphate; a possible medicinal dose of magnesia sulphate might amount to 56·7 grms. (2 oz.), the more usual dose being half that quantity. Lastly, among the insane there are found patients who will eat plaster-of-Paris, earth, and similar matters, so that, in special cases, a very large amount of combined sulphuric acid may be found in the intestinal tract, without any relation to poisoning by the free acid; but in such instances it must be rare, indeed, that surrounding circumstances or pathological evidence will not give a clue to the real state of affairs.

II.--Hydrochloric Acid.

§ 68. General Properties.--Hydrochloric acid, otherwise called muriatic acid, spirit of salt, is, in a strictly chemical sense, a pure gas, composed of 97·26 per cent. of chlorine, and 2·74 per cent. of hydrogen; but, in an ordinary sense, it is a liquid, being a solution of the gas itself.

Hydrochloric acid is made on an enormous scale in the United Kingdom, the production being estimated at about a million tons annually.

The toxicology of hydrochloric acid is modern, for we have no evidence that anything was known of it prior to the middle of the seventeenth century, when Glauber prepared it in solution, and, in 1772, Priestley, by treating common salt with sulphuric acid, isolated the pure gas.

The common liquid hydrochloric acid of commerce has a specific gravity of from 1·15 to 1·20, and contains usually less than 40 parts of hydrochloric acid in the 100 parts. The strength of pure samples of hydrochloric acid can be told by the specific gravity, and a very close approximation, in default of tables, may be obtained by simply multiplying the decimal figures of the specific gravity by 200. For example, an acid of 1·20 gravity would by this rule contain 40 per cent. of real acid, for ·20 × 200 = 40.

The commercial acid is nearly always a little yellow, from the presence of iron derived from metallic retorts, and usually contains small quantities of chloride of arsenic,[84] derived from the sulphuric acid; but the colourless hydrochloric acid specially made for laboratory and medicinal use is nearly always pure.

[84] Some samples of hydrochloric acid have been found to contain as much as 4 per cent. of chloride of arsenic, but this is very unusual. Glenard found as a mean 2·5 grammes, As₂O₃ per kilogramme.

The uses of the liquid acid are mainly in the production of chlorine, as a solvent for metals, and for medicinal and chemical purposes. Its properties are briefly as follows:--

It is a colourless or faintly-yellow acid liquid, the depth of colour depending on its purity, and especially its freedom from iron. The liquid is volatile, and can be separated from fixed matters and the less volatile acids by distillation; it has a strong attraction for water, and fumes when exposed to the air, from becoming saturated with aqueous vapour. If exposed to the vapour of ammonia, extremely dense clouds arise, due to the formation of the solid ammonium chloride. The acid, boiled with a small quantity of manganese binoxide, evolves chlorine. Dioxide of lead has a similar action; the chlorine may be detected by its bleaching action on a piece of paper dipped in indigo blue; a little zinc foil immersed in the acid disengages hydrogen. These two tests--viz., the production of chlorine by the one, and the production of hydrogen by the other--separate and reveal the constituent parts of the acid. Hydrochloric acid, in common with chlorides, gives a dense precipitate with silver nitrate. The precipitate is insoluble in nitric acid, but soluble in ammonia; it melts without decomposition. Exposed to the light, it becomes of a purple or blackish colour. Every 100 parts of silver chloride are equal to 25·43 of hydrochloric acid, HCl, and to 63·5 parts of the liquid acid of specific gravity 1·20.

The properties of pure hydrochloric acid gas are as follows:--Specific gravity 1·262, consisting of equal volumes of hydrogen and chlorine, united without condensation. 100 cubic inches must therefore have a weight of 39·36 grains. The gas was liquefied by Faraday by means of a pressure of 40 atmospheres at 10°; it was colourless, and had a less refractive index than water.

Water absorbs the gas with avidity, 100 volumes of water absorbing 48,000 volumes of the gas, and becoming 142 volumes. The solution has all the properties of strong hydrochloric acid, specific gravity 1·21. The dilute hydrochloric acid of the Pharmacopœia should have a specific gravity of 1·052, and be equivalent to 10·58 per cent. of HCl.

§69. =Statistics of Poisoning by Hydrochloric Acid.=--The following tables give the deaths, with age and sex distribution, due to hydrochloric acid for ten years (1883-92):--

DEATHS FROM HYDROCHLORIC ACID IN ENGLAND AND WALES DURING THE TEN YEARS ENDING 1892.

ACCIDENT OR NEGLIGENCE.

Ages, Under 1-5 5-15 15-25 25-65 65 and Total 1 above Males, 1 16 2 ... 26 3 48 Females, ... 8 ... ... 9 1 18 ---------------------------------------------------- Totals, 1 24 2 ... 35 4 66 ----------------------------------------------------

SUICIDE.

Ages, 5-15 15-25 25-65 65 and Total above Males, ... 2 73 8 83 Females, 1 8 42 65 116 --------------------------------------- Totals, 1 10 115 73 199 ---------------------------------------

In 1889 a solitary case of the murder of a child is on record from hydrochloric acid; hence, with that addition, the total deaths from hydrochloric acid amount to 266 in the ten years, or about 26 a year.

§ 70. =Fatal Dose.=--The dose which destroys life is not known with any accuracy. In two cases, adults have been killed by 14 grms. (half an ounce) of the commercial acid; but, on the other hand, recovery is recorded when more than double this quantity has been taken. A girl, fifteen years of age, died from drinking a teaspoonful of the acid.[85]

[85] Brit. Med. Journ., March, 1871.

§ 71. =Amount of Free Acid in the Gastric Juice.=--Hydrochloric acid exists in the gastric juice. This was first ascertained by Prout[86] in 1824; he separated it by distillation. The observation was afterwards confirmed by Gmelin,[87] Children,[88] and Braconnot.[89] On the other hand, Lehmann[90] pointed out that, as the stomach secretion contained, without doubt, lactic acid, the act of distillation, in the presence of this lactic acid, would set free hydrochloric acid from any alkaline chlorides. Blondlot and Cl. Bernard also showed that the gastric juice possessed no acid which would dissolve oxalate of lime, or develop hydrogen when treated with iron filings; hence there could not be free hydrochloric acid which, even in a diluted state, would respond to both these tests. Then followed the researches of C. Schmidt,[91] who showed that the gastric secretion of men, of sheep, and of dogs contained more hydrochloric acid than would satisfy the bases present; and he propounded the view that the gastric juice does not contain absolutely free hydrochloric acid, but that it is in loose combination with the pepsin.

[86] Philosophical Transactions, 1824, p. 45.

[87] P. Tiedmann and L. Gmelin, Die Verdauung nach Versuchen, Heidelberg u. Leipsic, 1826, i.

[88] Annals of Philosophy, July, 1824.

[89] Ann. de Chim. t. lix. p. 348.

[90] Journal f. prakt. Chemie, Bd. xl. 47.

[91] Bidder u. Schmidt, Verdauungs-Säfte, &c.

The amount of acid in the stomach varies from moment to moment, and therefore it is not possible to say what the average acidity of gastric juice is. It has been shown that in the total absence of free hydrochloric acid digestion may take place, because hydrochloric acid forms a compound with pepsin which acts as a solvent on the food. The amount of physiologically active acid varies with the food taken. It is smallest when carbohydrates are consumed, greatest with meat. The maximum amount that Jaksch found in his researches, when meat was ingested, was ·09 per cent. of hydrochloric acid. It is probable that anything above 0·2 per cent. of hydrochloric acid is either abnormal or owing to the recent ingestion of hydrochloric acid.

§ 72. =Influence of Hydrochloric Acid on Vegetation.=--Hydrochloric acid fumes, if emitted from works on a large scale, injure vegetation much. In former years, before any legal obligations were placed upon manufacturers for the condensing of the volatile products, the nuisance from this cause was great. In 1823, the duty on salt being repealed by the Government, an extraordinary impetus was given to the manufacture of hydrochloric acid, and since all the volatile products at that time escaped through short chimneys into the air, a considerable area of land round the works was rendered quite unfit for growing plants. The present law on the subject is, that the maximum quantity of acid escaping shall not exceed 2 grains per cubic foot of the air, smoke, or chimney gases; and, according to the reports of the alkali inspectors, the condensation by the improved appliances is well within the Act, and about as perfect as can be devised.

It appears from the reports of the Belgian Commission in 1855, when virtually no precautions were taken, that the gases are liable to injure vegetation to the extent of 2000 metres (2187 yards) around any active works; the more watery vapour the air contains, the quicker is the gas precipitated and carried to the earth. If the action of the vapour is considerable, the leaves of plants dry and wither; the chlorophyll becomes modified, and no longer gives the normal spectrum, while a thickening of the rind of trees has also been noticed. The cereals suffer much; they increase in stalk, but produce little grain. The leguminosæ become spotted, and have an air of dryness and want of vigour; while the potato, among plants utilised for food, appears to have the strongest resistance. Vines are very sensitive to the gas. Among trees, the alder seems most sensitive; then come fruit-trees, and last, the hardy forest-trees--the poplar, the ash, the lime, the elm, the maple, the birch, and the oak.[92]

[92] Those who desire to study more closely the effect of acids generally on vegetation may consult the various papers of the alkali inspectors contained in the Local Government Reports. See also Schubarth, Die saueren Gase, welche Schwefelsäure- und Soda-Fabriken verbreiten. Verhandlungen des Vereins zur Beförderung des Gewerbefleisses in Preussen, 1857, S. 135. Dingler’s Journal, Bd. 145, S. 374-427.

Christel, Ueber die Einwirkung von Säuren-Dämpfen auf die Vegetation.

Arch. f. Pharmacie, 1871, p. 252.

Vierteljahrsschrift für gerichtliche Medicin, 17 Bd. S. 404, 1872.

§73. =Action upon Cloth and Manufactured Articles.=--On black cloth the acid produces a green stain, which is not moist and shows no corrosion. On most matters the stain is more or less reddish; after a little time no free acid may be detected, by simply moistening the spot; but if the stain is cut out and boiled with water, there may be some evidence of free acid. The absence of moisture and corrosion distinguishes the stain from that produced by sulphuric acid.

§74. =Poisonous Effects of Hydrochloric Acid Gas.=--Eulenberg[93] has studied the effects of the vapour of this acid on rabbits and pigeons. One of these experiments may be cited in detail. Hydrochloric acid gas, prepared by heating together common salt and sulphuric acid, was passed into a glass shade supported on a plate, and a rabbit was placed in the transparent chamber thus formed. On the entrance of the vapour, there was immediate blinking of the eyes, rubbing of the paws against the nostrils, and emission of white fumes with the expired breath, while the respiration was irregular (40 to the minute). After the lapse of ten minutes, the gas was again introduced, until the atmosphere was quite thick; the symptoms were similar to those detailed above, but more violent; and in fourteen minutes from the commencement, the rabbit sank down on its right side (respirations 32). When twenty-two minutes had elapsed, the gas was again allowed to enter. The rabbit now lay quiet, with closed eyes and laboured respiration, and, finally, after half-an-hour of intermittent exposure to the gas, the animal was removed.

[93] Gewerbe Hygiene, Berlin, 1876, S. 51.

The cornea were opalescent, and the eyes filled with water; there was frequent shaking of the head and working of the forepaws. After three minutes’ exposure to the air, the respirations were found to be 128 per minute; this quickened respiration lasted for an hour, then gave place to a shorter and more superficial breathing. On the second day after the experiment, the rabbit suffered from laboured respiration (28 to the minute) and pain, and there was a rattling in the bronchial tubes. The animal died on the third day, death being preceded by slow respiration (12 to the minute).

The appearances twenty-four hours after death were as follows:--The eyes were coated with a thick slime, and both cornea were opalescent; there was strong rigidity of the body. The pia mater covering the brain was everywhere hyperæmic, and at the hinder border of both hemispheres appeared a small clot, surrounded by a thin layer of bloody fluid. The plex. venos spin. was filled with coagulated blood, and there was also a thin extravasation of blood covering the medulla and pons. The lungs were mottled bright brown-red; the middle lobe of the right lung was dark brown, solid, and sank in water; the lower lobe of the same lung and the upper lobe of the left lung were nearly in a similar condition, but the edges were of a bright red. The parenchyma in the darker places on section did not crepitate. On the cut surface was a little dark, fluid, weakly-acid blood; the tracheal mucous membrane was injected. The heart was filled with thick coagulated blood; the liver was congested, of a reddish-brown colour, and rich in dark, fluid blood: in the vena cava inferior was coagulated blood. The kidneys were not hyperæmic; the intestines were superficially congested.

I think there can be little doubt that the symptoms during life, and the appearances after death, in this case are perfectly consistent with the following view:--The vapour acts first as a direct irritant, and is capable of exciting inflammation in the lung and bronchial tissues; but besides this, there is a secondary effect, only occurring when the gas is in sufficient quantity, and the action sufficiently prolonged--viz., a direct coagulation of the blood in certain points of the living vessels of the lungs. The consequence of this is a more or less general backward engorgement, the right side of the heart becomes distended with blood, and the ultimate cause of death is partly mechanical. The hyperæmia of the brain membranes, and even the hæmorrhages, are quite consistent with this view, and occur in cases where the obstruction to the circulation is of a coarser and more obvious character, and can therefore be better appreciated.

§ 75. =Effects of the Liquid Acid.=--There is one distinction between poisoning by hydrochloric and the other mineral acids--namely, the absence of corrosion of the skin. Ad. Lesser[94] has established, by direct experiment, that it is not possible to make any permanent mark on the skin by the application even of the strongest commercial acid (40 per cent.). Hence, in any case of suspected poisoning by acid, should there be stains on the lips and face as from an acid, the presumption will be rather against hydrochloric. The symptoms themselves differ very little from those produced by sulphuric acid. The pathological appearances also are not essentially different, but hydrochloric is a weaker acid, and the extensive disorganisation, solution, and perforation of the viscera, noticed occasionally with sulphuric acid, have never been found in hydrochloric acid poisoning. We may quote here the following case:--

[94] Virchow’s Archiv f. path. Anat., Bd. 83, Hft. 2, S. 215, 1881.

A woman, under the influence of great and sudden grief--not unmixed with passion--drew a bottle from her pocket, and emptied it very quickly. She immediately uttered a cry, writhed, and vomited a yellow-green fluid. The abdomen also became enlarged. Milk was given her, but she could not swallow it, and death took place, in convulsions, two hours after the drinking of the poison.

The post-mortem appearances were briefly as follows:--Mouth and tongue free from textural change: much gas in the abdomen, more especially in the stomach; the membranes of the brain congested; the lungs filled with blood. The stomach was strongly pressed forward, of a dark brown-red, and exhibited many irregular blackish spots, varying from two lines to half an inch in diameter (the spots were drier and harder than the rest of the stomach); the mucous membrane, internally, was generally blackened, and changed to a carbonised, shaggy, slimy mass, while the organ was filled with a blackish homogeneous pulp, which had no odour. The gullet was also blackened. A considerable quantity of hydrochloric acid was separated from the stomach.[95]

[95] Preuss. Med. Vereinszeit. u. Friederichs Blätter f. gerichtl. Anthropologie, 1858, Hft. 6, S. 70.

The termination in this instance was unusually rapid. In a case detailed by Casper,[96] in which a boy drank an unknown quantity of acid, death took place in seven hours. In Guy’s Hospital museum, the duodenum and stomach are preserved of a patient who is said to have died in nine and a half hours from half an ounce of the acid. The same quantity, in a case related by Taylor, caused death in eighteen hours. From these and other instances, it may be presumed that death from acute poisoning by hydrochloric acid will probably take place within twenty-four hours. From the secondary effects, of course, death may take place at a remote period, e.g., in a case recorded by Dr. Duncan (Lancet, April 12, 1890), a man drank about 1 oz. of HCl accidentally, was admitted to Charing Cross Hospital the same day, and treated with small quantities of sodium carbonate, and fed by the rectum. On the eighth day he brought up 34 oz. of blood; in a month he left apparently perfectly well, but was admitted again in about six weeks, and died of contraction of the stomach and stricture of the pylorus on the ninety-fourth day.

[96] Case 230.--Gerichtliche Medicin, 6th Ed., Berlin, 1876.

§76. =Post-mortem Appearances.=--The pathological appearances are very similar to those found in the case already detailed; though the skin of the face may not be eroded in any way by the acid, yet the more delicate mucous membrane of the mouth, gullet, &c., appears mostly to be changed, and is usually white or whitish-brown. There is, however, in the museum of the Royal College of Surgeons the stomach and gullet (No. 2386c.) of an infant thirteen months old; the infant drank a tea-cupful of strong hydrochloric acid, and died nine hours after the dose. The pharynx and the upper end of the gullet is quite normal, the corrosive action commencing at the lower end, so that, although the acid was concentrated, not the slightest effect was produced on the delicate mucous membrane of the throat and upper part of the gullet. The lower end of the gullet and the whole of the stomach were intensely congested; the rugæ of the latter were ecchymosed and blackened by the action of the acid. There were also small hæmorrhages in the lungs, which were ascribed to the action of the acid on the blood. Perforation of the stomach has not been noticed in hydrochloric acid poisoning.

In Guy’s Hospital museum (prep. 1799¹⁰), the stomach and duodenum of the case mentioned exhibit the mucous membrane considerably injected, with extravasations of blood, which, at the time when the preparation was first arranged, were of various hues, but are now somewhat altered, through long keeping in spirit. In St. George’s Hospital museum (ser. x. 43, d. 200) are preserved the stomach and part of the duodenum of a person who died from hydrochloric acid. The case is detailed in the Medical Times and Gazette for 1853, vol. ii. p. 513. The whole inner surface appears to be in a sloughing state, and the larynx and lung were also inflamed.

A preparation, presented by Mr. Bowman to King’s College Hospital museum, exhibits the effects of a very large dose of hydrochloric acid. The gullet has a shrivelled and worm-eaten appearance; the stomach is injected with black blood, and was filled with an acid, grumous matter.[97]

[97] A drawing of parts of the gullet and stomach is given in Guy and Ferrier’s Forensic Medicine.

Looking at these and other museum preparations illustrating the effects of sulphuric and hydrochloric acids, I was unable (in default of the history of the cases) to distinguish between the two, by the naked eye appearances, save in those cases in which the disorganisation was so excessive as to render hydrochloric acid improbable. On the other hand, the changes produced by nitric acid are so distinctive, that it is impossible to mistake its action for that of any other acid. The nitric acid pathological preparations may be picked out at a glance.

Detection and Estimation of Free Hydrochloric Acid.

§ 77. (1) =Detection.=--A large number of colouring reagents have been proposed as tests for the presence of free mineral acid; among the best is methyl-aniline violet decolorised by a large amount of hydrochloric acid; the violet turns to green with a moderate quantity, and to blue with a small quantity.

=Tropæolin= (00), in the presence of free mineral acid, strikes a ruby-red to a dark brown-red.

=Congo-red= is used in the form of paper dyed with the material; large amounts of free hydrochloric acid strike blue-black, small quantities blue.

=Günzburg’s test= is 2 parts phloroglucin and 1 part vanillin, dissolved in 100 parts of alcohol. Fine red crystals are precipitated on the addition of hydrochloric acid. To test the stomach contents for free hydrochloric acid by means of this reagent, equal parts of the fluid and the test are evaporated to dryness in the water-bath in a porcelain dish. If free hydrochloric acid be present, the evaporated residue shows a red colour; 1 mgrm. of acid can by this test be detected. The reaction is not interfered with by organic acids, peptones, or albumin.

Jaksch speaks highly of benzopurpurin as a test. Filter-paper is soaked in a saturated aqueous solution of benzopurpurin 6 B (the variety 1 or 4 B is not so sensitive), and the filter-paper thus prepared allowed to dry. On testing the contents of the stomach with the reagent, if there is more than 4 parts per 1000 of hydrochloric acid the paper is stained intensely blue-black; but if the colour is brown-black, this is from butyric or lactic acids, or from a mixture of these acids with hydrochloric acid. If the paper is washed with pure ether, and the colour was due only to organic acids, the original hue of the paper is restored; if the colour produced was due to a mixture of mineral and organic acids, the brown-black colour is weakened; and, lastly, if due to hydrochloric acid alone, the colour is not altered by washing with ether. Acid salts have no action, nor is the test interfered with by large amounts of albumins and peptones.

A. Villiers and M. Favolle[98] have published a sensitive test for hydrochloric acid. The test consists of a saturated aqueous solution of colourless aniline, 4 parts; glacial acetic acid, 1 part; 0·1 mgrm. of hydrochloric acid strikes with this reagent a blue colour, 1 mgrm. a black colour. The liquid under examination is brought by evaporation, or by the addition of water, to 10 c.c. and placed in a flask; to this is added 5 c.c. of a mixture of equal parts of sulphuric acid and water, then 10 c.c. of a saturated solution of potassic permanganate, and heated gently, conveying the gases into 3 to 5 c.c. of the reagent contained in a test-tube immersed in water. If, however, bromine or iodine (one or both) should be present, the process is modified as follows:--The hydracids are precipitated by silver nitrate; the precipitate is washed, transferred to a small flask, and treated with 10 c.c. of water and 1 c.c. of pure ammonia. With this strength of ammonia the chloride of silver is dissolved easily, the iodide not at all, and the bromide but slightly. The ammoniacal solution is filtered, boiled, and treated with SH₂; the excess of SH₂ is expelled by boiling, the liquid filtered, reduced to 10 c.c. by boiling or evaporation, sulphuric acid and permanganate added as before, and the gases passed into the aniline. The process is inapplicable to the detection of chlorides or hydrochloric acid if cyanides are present, and it is more adapted for traces of hydrochloric acid than for the quantities likely to be met with in a toxicological inquiry.

[98] Comptes Rend., cxviii.

(2) =Quantitative estimation of Free Hydrochloric Acid.=--The contents of the stomach are diluted to a known volume, say 250 or 500 c.c. A fractional portion is taken, say 10 c.c., coloured with litmus or phenol-phthalein, and a decinormal solution of soda added drop by drop until the colour changes; this gives total acidity. Another 10 c.c. is shaken with double its volume of ether three times, the fluid separated from ether and titrated in the same way; this last titration will give the acidity due to mineral acids and acid salts;[99] if the only mineral acid present is hydrochloric acid the results will be near the truth if reckoned as such, and this method, although not exact for physiological research, is usually sufficient for the purpose of ascertaining the amount of hydrochloric acid or other mineral acids in a case of poisoning. It depends on the fact that ether extracts free organic acids, such as butyric and lactic acids, but does not extract mineral acids.

[99] To distinguish between acidity due to free acid and acid salts, or to acidity due to the combined action of acid salts and free acids, the method of Leo and Uffelmann is useful. A fractional portion of the contents of the stomach is triturated with pure calcium carbonate; if all the acidity is due to free acid, the fluid in a short time becomes neutral to litmus; if, on the other hand, the acidity is due entirely to acid salts, the fluid remains acid; or, if due to both acid and acid salts, there is a proportionate diminution of acidity due to the decomposition of the lime carbonate by the free acid. A quantitative method has been devised upon these principles. See Leo, Diagnostik der Krankheiten der Verdauungsorgane, Hirschwald, Berlin, 1890.

The free mineral acid, after extracting the organic acid by ether, can also be saturated with cinchonine; this hydrochlorate of cinchonine is extracted by chloroform, evaporated to dryness, and the residue dissolved in water acidified by nitric acid and precipitated by silver nitrate; the silver chloride produced is collected on a small filter, washed, and the filter, with its contents, dried and ignited in a porcelain crucible; the silver chloride, multiplied by 0·25426, equals HCl.

The best method of estimating free hydrochloric acid in the stomach is that of Sjokvist as modified by v. Jaksch;[100] it has the disadvantage of its accuracy being interfered with by phosphates; it also does not distinguish between actual free HCl and the loosely bound HCl with albuminous matters,--this in a toxicological case is of small importance, because the quantities of HCl found are likely to be large.

[100] Klinische Diagnostik, Dr. Rudolph v. Jaksch, Wien u. Leipzig, 1892. Clinical Diagnosis. English Translation, by Dr. Cagney. Second Edition. London: Charles Griffin & Co., Limited.

The method is based upon the fact that if carbonate of baryta be added to the contents of the stomach, the organic acids will decompose the barium carbonate, forming butyrate, acetate, lactate, &c., of barium; and the mineral acids, such as hydrochloric acid, will combine, forming salts of barium.

On ignition, chloride of barium will be unaffected, while the organic salts of barium will be converted into carbonate of barium, practically insoluble in carbonic acid free water.

The contents of the stomach are coloured with litmus, and barium carbonate added until the fluid is no longer acid (as shown by the disappearance of the red colour); then the contents are evaporated to dryness in a platinum dish, and ignited at a dull red heat; complete burning to an ash is not necessary. After cooling, the burnt mass is repeatedly exhausted with boiling water and filtered; the chloride of barium is precipitated from the filtrate by means of dilute sulphuric acid; the barium sulphate filtered off, washed, dried, and, after ignition, weighed; 233 parts of barium sulphate equal 73 parts of HCl.

A method somewhat quicker, but depending on the same principles, has been suggested by Braun.[101] A fractional part, say 10 c.c., of the fluid contents is coloured by litmus and titrated with decinormal soda. To the same quantity is added 2 or 3 more c.c. of decinormal soda than the quantity used in the first titration; this alkaline liquid is evaporated to dryness and ultimately ignited. To the ash is now added exactly the quantity of decinormal sulphuric acid as the decinormal soda last used to make it alkaline--that is to say, if the total acidity was equal to 3·6 d.n. soda, and 5·0 d.n. soda was added to the 10 c.c. evaporated to dryness and burned, then 5·6 c.c. of d.n. sulphuric acid is added to the ash. The solution is now warmed to get rid of carbon dioxide, and, after addition of a little phenolphthalein, titrated with d.n. soda solution until the change of colour shows saturation, the number of c.c. used, multiplied by 0·00365, equals the HCl.

[101] Op. cit., S. 157.

§78. In investigating the stains from hydrochloric acid on fabrics, or the leaves of plants, any free hydrochloric acid may be separated by boiling with water, and then investigating the aqueous extract. Should, however, the stain be old, all free acid may have disappeared, and yet some of the chlorine remain in organic combination with the tissue, or in combination with bases. Dr. Angus Smith has found weighed portions of leaves, &c., which had been exposed to the action of hydrochloric acid fumes, richer in chlorides than similar parts of the plants not thus exposed.

The most accurate method of investigation for the purpose of separating chlorine from combination with organic matters is to cut out the stained portions, weigh them, and burn them up in a combustion-tube, the front portion of the tube being filled with caustic lime known to be free from chlorides; a similar experiment must be made with the unstained portions. In this way a considerable difference may often be found; and it is not impossible, in some instances, to thus detect, after the lapse of many years, that certain stains have been produced by a chlorine-holding substance.

III.--Nitric Acid.

§ 79. =General Properties.=--Nitric acid--commonly known in England as aqua fortis, chemically as nitric acid, hydric nitrate, or nitric monohydrate--is a mono-hydrate of nitrogen pentoxide (N₂O₅), two equivalents, or 126 parts, of nitric acid containing 108 of N₂O₅, and 18 of H₂O. Anhydrous nitric acid, or nitrogen pentoxide, can be obtained by passing, with special precautions, dry chlorine over silver nitrate; the products are free oxygen and nitrogen pentoxide, according to the following equation:--

Silver Chlorine. Silver Nitrogen Oxygen. Nitrate. Chloride. Pentoxide. Ag₂O,N₂O₅ + 2Cl = 2AgCl + N₂O₅ + O

By surrounding the receiver with a freezing mixture, the acid is condensed in crystals, which dissolve in water, with emission of much heat, forming nitric acid. Sometimes the crystals, though kept in sealed tubes, decompose, and the tube, from the pressure of the liberated gases, bursts with a dangerous explosion.

Pure nitric acid has a specific gravity of 1·52, and boils at 98°. Dr. Ure examined the boiling point and other properties of nitric acid very fully. An acid of 1·5 specific gravity boils at 98·8°; of specific gravity 1·45, at 115·5°; specific gravity 1·40, at 118·8°; of specific gravity 1·42, at 122·8°. The acid of specific gravity 1·42 is the standard acid of the British Pharmacopœia. It can always be obtained by distilling either strong or moderately weak nitric acid; for, on the one hand, the acid on distillation gets weaker until the gravity of 1·42 is reached, or, on the other, it becomes stronger.

There is little doubt that acid of 1·42 gravity is a definite hydrate, consisting of 1 atom of dry acid and 4 atoms of water; it corresponds to 75 per cent.[102] of the liquid acid HNO₃. There are also at least two other hydrates known--one an acid of 1·485 specific gravity, corresponding to 1 atom of dry acid and 2 of water, and an acid of specific gravity 1·334, corresponding to 1 atom of dry acid and 7 atoms of water.

[102] The British Pharmacopœia states that the 1·42 acid equals 70 per cent. of HNO₃; but this is not in accordance with Ure’s Tables, nor with the facts.

In Germany the officinal acid is of 1·185 specific gravity, corresponding to about 30 per cent. of HNO₃. The dilute nitric acid of the Pharmacopœia is a colourless liquid, of specific gravity 1·101, and should contain about 17·4 per cent. of acid. The acids used in various industries are known respectively as dyers’ and engravers’ acid. Dyers’ acid has a specific gravity of 1·33 to 1·34 (66° to 68° Twad.), that is, strength from 56 to 58 per cent. of HNO₃. Engravers’ acid is stronger; being of 1·40 specific gravity (80° Twad.); and contains 70 per cent. of HNO₃. Although the pure acid of commerce is (and should be) almost colourless, most commercial specimens are of hues from yellow up to deep red. An acid saturated with red oxides of nitrogen is often known as “fuming nitric acid.”

§ 80. =Use in the Arts.=--Nitric acid is employed very extensively in the arts and manufactures. The dyer uses it as a solvent for tin in the preparation of valuable mordants for calico and other fabrics; the engraver uses it for etching copper. It is an indispensable agent in the manufacture of gun-cotton, nitro-glycerin, picric acid, and sulphuric acid; it is also used in the manufacture of tallow, in preparing the felt for hats, and in the gilding trades. It is said to be utilised to make yellowish or fawn-coloured spots on cigar leaves, so as to give them the appearance of age and quality. It is also used as a medicine.

§ 81. =Statistics of Poisoning by Nitric Acid.=--In the ten years 1883-1892 no case of murder was ascribed to nitric acid, but it caused accidentally 25 deaths, and was used in 27 cases of suicide.

The following tables give the age and sex distribution of these deaths:--

DEATHS IN ENGLAND AND WALES DURING THE TEN YEARS ENDING 1892 FROM NITRIC ACID.

ACCIDENT OR NEGLIGENCE.

Ages, 1-5 5-15 15-25 25-65 65 and Total above Males, 6 2 1 9 ... 18 Females, 3 ... ... 4 ... 7 -------------------------------------- Totals, 9 2 1 13 ... 25 --------------------------------------

SUICIDE.

Ages, 15-25 25-65 65 and Total above Males, 3 14 1 18 Females, 1 8 ... 9 ---------------------------- Totals, 4 22 1 27 ----------------------------

§ 82. =Fatal Dose.=--The dose which causes death has not been ascertained with any exactness. As in the case of sulphuric acid, we may go so far as to say that it is possible for a few drops of the strong acid to be fatal, for if brought into contact with the vocal apparatus, fatal spasm of the glottis might be excited. The smallest dose on record is 7·7 grms. (2 drachms), which killed a child aged 13.

§ 83. =Action of Nitric Acid on Vegetation.=--Nitric acid acts on plants injuriously in a two-fold manner--viz., by direct corrosive action, and also by decomposing the chlorides which all plants contain, thus setting free chlorine, which decomposes and bleaches the chlorophyll. The action is most intense on soft and delicate leaves, such as those of clover, the cabbage, and all the cruciferæ. The tobacco plant is particularly injured by nitric acid. Next to all herbaceous plants, trees, such as the apple, pear, and fruit trees, generally suffer. The coniferæ, whether from their impregnation with resin, or from some other cause, possess a considerable resisting-power against nitric acid vapours, and the same is true as regards the cereals; in the latter case, their siliceous armour acts as a preserving agent.

§ 84. =Nitric Acid Vapour.=--The action of nitric acid in a state of vapour, as evolved by warming potassic nitrate and sulphuric acid together, has been studied by Eulenberg. A rabbit was placed under a shade into which 63 grains of nitric acid in a state of vapour were introduced. From the conditions of the experiment, some nitric peroxide must also have been present. Irritation of the external mucous membranes and embarrassment in breathing were observed. The animal in forty-five minutes was removed, and suffered afterwards from a croupous bronchitis, from which, however, it completely recovered in eleven days. A second experiment with the same animal was followed by death. On inspection, there was found strong injection of the cerebral membranes, with small extravasations of blood; the lungs were excessively congested; the right middle lobe especially was of a liver-brown colour, and empty of air: it sank in water.

O. Lassar[103] has also made a series of researches on the influence of nitric acid vapour, from which he concludes that the acid is not absorbed by the blood, but acts only by its mechanical irritation, for he could not trace, by means of an examination of the urine, any evidence of such absorption.

[103] Hoppe-Seyler’s Zeitschrift f. physiol. Chemie, Bd. i. S. 165-173, 1877-78.

There are a few instances on record of the vapour having been fatal to men; for example, the well-known case of Mr. Haywood, a chemist of Sheffield, may be cited. In pouring a mixture of nitric and sulphuric acids from a carboy of sixty pounds capacity, the vessel broke, and for a few minutes he inhaled the mixed fumes. He died eleven hours after the accident, although for the first three hours there were scarcely any symptoms of an injurious effect having been produced. On inspection, there was found intense congestion of the windpipe and bronchial tubes, with effusion of blood in the latter. The lining membrane of the heart and aorta was inflamed; unfortunately, the larynx was not examined.[104]

[104] Lancet, April 15, 1854, p. 430.

A very similar case happened in Edinburgh in 1863.[105] Two young men were carrying a jar of nitric acid; the jar broke, and they attempted to wipe up the acid from the floor. The one died ten hours after the accident, the other in less than twenty-four hours. The symptoms were mainly those of difficult breathing, and it is probable that death was produced from suffocation. Dr. Taylor relates also, that having accidentally inhaled the vapour in preparing gun-cotton, he suffered from severe constriction of the throat, tightness in the chest, and cough, for more than a week.[106]

[105] Chemical News, March 14, 1863, p. 132.

[106] Principles and Practice of Medical Jurisprudence, vol. i., 1873, p. 218.

§ 85. =Effects of Liquid Nitric Acid.=--Poisoning by nitric acid, though still rare, is naturally more frequent than formerly. At the beginning of this century, Tartra[107] wrote a most excellent monograph on the subject, and collated all the cases he could find, from the first recorded instances related by Bembo[108] in Venetian history, down to his own time. The number of deaths in those 400 years was but fifty-five, while, in our century, at least fifty can be numbered. Most of these (74 per cent.) are suicidal, a very few homicidal, the rest accidental. In one of Tartra’s cases, some nitric acid was placed in the wine of a drunken woman, with fatal effect. Osenbrüggen[109] relates the case of a father murdering his six children by means of nitric acid; and C. A. Büchner[110] that of a soldier who poured acid into the mouth of his illegitimate infant. A curious case is one in which a man poisoned his drunken wife by pouring the acid into her right ear; she died after six weeks’ illness. All these instances prove again, if necessary, that the acid is only likely to be used with murderous intent in the case of young children, or of sleeping, drunken, or otherwise helpless people.

[107] Tartra, A. E., Dr., Traité de l’Empoisonnement par l’Acide Nitrique, Paris, An. 10 (1802), pp. 300.

[108] Bembo Cardinalis, Rerum Venetarium Historiæ, lib. xii., lib. i. p. 12, Paris Ed., 1551.

[109] Allgem.-Deutsche Strafrechtszeitung, herausgeg. v. Frz. v. Holtzendorff, 5 Jahrg., 1865, Hft. 5, S. 273.

[110] Friederich’s Blätter f. ger. Med., 1866, Hft. 3, S. 187.

As an example of the way in which accidents are brought about by heedlessness, may be cited the recent case of a woman who bought a small quantity of aqua fortis for the purpose of allaying toothache by a local application. She attempted to pour the acid direct from the bottle into the cavity of the tooth; the acid went down her throat, and the usual symptoms followed. She threw up a very perfect cast of the gullet (preserved in University College museum), and rapidly died. Nitric acid has been mistaken for various liquids, and has also been used by injection as an abortive, in every respect having a toxicological history similar to that of sulphuric acid.

§ 86. =Local Action.=--When strong nitric acid comes in contact with organic matters, there is almost constantly a development of gas. The tissue is first bleached, and then becomes of a more or less intense yellow colour. Nitric acid spots on the skin are not removed by ammonia, but become of an orange-red when moistened with potash and a solution of cyanide of potassium. The yellow colour seems to show that picric acid is one of the constant products of the reaction; sulphide of ammonium forms a sort of soap with the epidermis thus attacked, and detaches it.

§ 87. =Symptoms.=--The symptoms and course of nitric acid poisoning differ in a few details only from those of sulphuric acid. There is the same instant pain and frequent vomiting, destruction of the mucous membranes, and, in the less severe cases, after-contraction of the gullet, &c.

One of the differences in the action of nitric and sulphuric acids is the constant development of gas with the former. This, without doubt, adds to the suffering. Tartra made several experiments on dead bodies, and showed that very considerable distension of the intestinal canal, by gaseous products, was the constant result; the tissues were corroded and almost dissolved, being transformed, ultimately, into a sort of greasy paste. The vomited matters are of a yellow colour, unless mixed with blood, when they are of a dirty-brown hue, with shreds of yellow mucus, and have the strong acid reaction and smell of nitric acid. The teeth may be partially attacked from the solvent action of the acid on the enamel. The fauces and tongue, at first blanched, soon acquire a citron-yellow, or even a brown colour; the whole cavity may swell and inflame, rendering the swallowing of liquids difficult, painful, and sometimes impossible. The air passages may also become affected, and in one case tracheotomy was performed for the relief of the breathing.[111] The stomach rejects all remedies; there are symptoms of collapse; quick, weak pulse, frequent shivering, obstinate constipation, and death (often preceded by a kind of stupor) in from eighteen to twenty-four hours. The intellectual faculties remain clear, save in a few rare instances.

[111] Arnott, Med. Gaz., vol. xii. p. 220.

C. A. Wunderlich has recorded an unusual case, in which the symptoms were those of dysentery, and the large intestine was found acutely inflamed, while the small one was little affected. The kidneys had the same appearance as in Bright’s disease.[112] The smallest fatal dose given by Taylor is from 2 drachms, which killed a child aged 13 years. Should the dose of nitric acid be insufficient to kill at once, or, what amounts to the same thing, should the acid be immediately diluted with water, or in some way be neutralised, the patient, as in the case of sulphuric acid, may yet die at a variable future time from stenosis of the gullet, impaired digestion, &c. For example, in an interesting case related by Tartra,[113] a woman, who had swallowed 42 grms. (1·5 oz.) of nitric acid, feeling acute pain, took immediately a quantity of water, and three hours afterwards was admitted into hospital, where she received appropriate treatment. At the end of a month she left, believing herself cured; but in a little while returned, and was re-admitted, suffering from marasmus, extreme weakness, and constant vomiting; ultimately she died. The post-mortem examination revealed extreme contraction of the intestinal canal throughout. The lumen would hardly admit a penholder. The stomach was no larger than an ordinary intestine, and adherent to adjacent organs; on its internal surface there were spots, probably cicatrices; there were also changes in the gullet, but not so marked. A somewhat similar case is related by the same author in his thirteenth observation. In the Middlesex Hospital there is preserved the stomach (No. 1363) of a man who died forty days after swallowing 2 ozs. of nitric acid diluted in a tumbler of water. The stomach is contracted, the mucous membrane of the lower part of the gullet, the lesser curvature, and the pyloric end of the stomach is extensively corroded, showing ulcerated patches commencing to cicatrize.

[112] De Actionibus quibusdam Acidi Nitrici Caustico in Corpus Humanum immissi. Programma Academ., Lipsiæ, 1857, 4.

[113] Op. cit.

§ 88. =Post-mortem Appearances.=--The pathological changes in the tongue, gullet, and stomach can be readily studied from the preparations in the different museums. The staining by the nitric acid appears unchanged to the naked eye for many years; hence, most of the nitric acid preparations are in an excellent state of preservation. A very good example of the pathological changes is to be found in Nos. 1049 and 1050, University College museum.

No. 1049 presents the tongue, pharynx, and larynx of a man who had swallowed a tea-cupful of nitric acid. The epithelium of the œsophagus is for the most part wanting, and hangs in shreds; the dorsum of the tongue, in front of the circumvallate papillæ, is excavated, and over its central part superficially ulcerated; in other places the tongue is encrusted with a thick, loose, fawn-coloured layer, formed probably of desquamated epithelium. The whole of the mucous surface is stained of a dirty yellow.

No. 1050 is a preparation showing the tongue, gullet, and stomach of a person who died from the effects of nitric acid. The tongue in places is smooth and glazed; in others, slightly depressed and excavated. On the anterior wall and lower portion of the gullet two large sloughs exist.

Although perforation of the stomach is not so common with nitric as with sulphuric acid, such an accident may occur, as shown in a preparation at Guy’s Hospital, in which there is a perforation at the cardiac end. All the mucous membrane has disappeared, and the inner surface is for the most part covered with flocculent shreds. Three ounces of nitric acid are said to have been swallowed, and the patient lived seventeen hours. There is the usual staining. There is also in the Middlesex Hospital (No. 1364) the œsophagus and stomach of a woman aged 30, who died six hours after swallowing 2 to 3 ozs. of strong nitric acid. The inner coats of the mucous membrane of the gullet and stomach are in part converted into opaque yellow and black eschars, and in part to a shreddy pulpy condition. At the most depending part of the stomach is a large ragged perforation, with pulpy margins, which allowed the contents of the stomach to escape into the peritoneal cavity.

In St. Bartholomew’s museum, there is a very good specimen (No. 1870) of the appearances in the gullet and stomach after poisoning by nitric acid. The case is detailed in St. Bartholomew’s Hospital Reports, vol. v. p. 247. A male died in fifteen hours after swallowing 1 oz. of nitric acid. The whole mucous membrane is wrinkled, or rather ploughed, into longitudinal furrows, the yellow discoloration stops abruptly, with an irregular border, at the commencement of the stomach, the epithelial and mucous coats of which are wanting--its surface being rough and of a brownish-red colour.

The following preparations are to be found in the museum of the London Hospital:--A. b. 1. and A. b. 8.--A. b. 1. shows the pharynx, œsophagus, larynx, and stomach of a young woman, who, after taking half an ounce of nitric acid, died in eight hours. The staining is very intense; as an unusual feature, it may be noted that the larynx is almost as yellow as the œsophagus. The abrasion or solution of the epithelium on the dorsum of the tongue has dissected out the circumvallate and fungiform papillæ, so that they project with unusual distinctness. The lining membrane of the gullet throughout is divided into minute squares by longitudinal and transverse furrows. The mucous membrane of the stomach appears wholly destroyed, and presents a woolly appearance.

A. b. 8. shows a very perfect cast of the œsophagus. The case was that of a woman, aged 35, who swallowed half an ounce of nitric acid. The symptoms for the first four days were the usual pain in the throat and stomach, which might be expected; the bowels were freely open, and the stools dark and offensive. On the sixth day, there was constant vomiting with offensive breath; on the ninth, the appearance of the patient was critical, and she threw up the cast preserved. She died on the tenth day after the taking of the acid. The gullet, stomach, trachea, and larynx were found after death much inflamed.

The following preparations are in St. Thomas’ Hospital:--P. 5.--a stomach with gullet attached. The stomach is covered with yellowish-green patches of false membrane and deposit; the gullet has the usual longitudinal furrows so characteristic of corrosive fluids.

P. 6. is also from a case of nitric acid poisoning. It shows the lining membrane of the stomach partly destroyed and shreddy, yet but little discoloured, the hue being a sort of delicate fawn.

To these may be added a case described and figured by Lesser; to a baby, a few days old, an unknown quantity of fuming nitric acid was given; the child made a gurgling, choking sound, and died in a few minutes. The corpse, nine days after death, showed no signs of decomposition. The tongue and gums were yellow, the gullet less so, the stomach still less, and the small intestine had no yellow tint; the whole of the mouth, gullet, and stomach showed the corrosive action of the acid. The graduation of tint, Lesser remarks, is what is not seen when the yellow colour is due to poisoning by chromic acid or by strong solution of ferric perchloride; in such cases, wherever the liquid has gone, there is a yellowness.[114]

[114] A. Lesser, Atlas der gerichtlichen Medicin, Berlin, 1884, Tafel i. fig. 2.

§ 89. =Detection and Estimation of Nitric Acid.=--The detection either of free nitric acid or of its salts is not difficult. Free nitric acid, after preliminary estimation of the total acidity by decinormal soda, may be separated by the cinchonine process given at p. 100. On precipitation by ammonia or soda solution, the nitrate of ammonia or soda (and, it may be, other similarly combined acids) remain in solution. If free nitric acid is present in small quantity only, it may be necessary to evaporate the filtrate from the quinine nearly to dryness, and to test the concentrated liquid for nitric acid. The ordinary tests are as follows:--

(1.) Nitrates, treated with mercury or copper and strong sulphuric acid, develop nitric oxide, recognised by red fumes, if mixed with air or oxygen.

(2.) A nitrate dissolved in a small quantity of water, with the addition of a crystal of ferrous sulphate (allowed to partially dissolve), and then of strong sulphuric acid--poured through a funnel with a long tube dipping to the bottom of the test-tube, so as to form a layer at the bottom--strikes a brown colour at the junction of the liquid. When the test is properly performed, there will be three layers--the uppermost being the nitrate solution, the middle ferrous sulphate, and the lowest sulphuric acid; the middle layer becomes of a smoky or black hue if a nitrate is present. Organic matter interferes much with the reaction.

(3.) Nitrates in solution, treated in the cold with a zinc copper couple, are decomposed first into nitrites, and then into ammonia. The nitrites may be detected by a solution of metaphenyldiamine, which strikes a red colour with an infinitesimal quantity. Hence, a solution which gives no red colour with metaphenyldiamine, when submitted to the action of a zinc copper couple, and tested from time to time, cannot contain nitrites; therefore, no nitrates were originally present.

(4.) Nitrates, on being treated with strong sulphuric acid, and then a solution of indigo carmine dropped in, decolorise the indigo; this is a useful test--not conclusive in itself, but readily applied, and if the cinchonine method of separation has been resorted to, with few sources of error.

There is a process of separating nitric acid direct from any organic tissue, which may sometimes be useful:--Place the substance in a strong, wide-mouthed flask, closed by a caoutchouc cork, and in the flask put a small, short test-tube, charged with a strong solution of ferrous chloride in hydrochloric acid. The flask is connected to the mercury pump (see fig. p. 47), and made perfectly vacuous by raising and lowering the reservoir. When this is effected, the tube SS′P is adjusted so as to deliver any gas evolved into a eudiometer, or other gas-measuring apparatus. By a suitable movement of the flask, the acid ferrous chloride is allowed to come in contact with the tissue, a gentle heat applied to the flask, and gases are evolved. These may be carbon dioxide, nitrogen, and nitric oxide. On the evolution of gas ceasing, the carbon dioxide is absorbed by passing up under the mercury a little caustic potash. When absorption is complete, the gas, consisting of nitrogen and nitric oxide, may be measured. A bubble or two of oxygen is now passed into the eudiometer; if nitric oxide is present, red fumes at once develop. On absorbing the excess of oxygen and the nitric peroxide by alkaline pyrogallate, and measuring the residual gas, it is easy to calculate how much nitric oxide was originally present, according to the principles laid down in “Foods,” p. 587.

It is also obvious that, by treating nitric oxide with oxygen, and absorbing the nitric peroxide present by an alkaline liquid of known strength and free from nitrates or ammonia, the resulting solution may be dealt with by a zinc copper couple, and the ammonia developed by the action of the couple directly estimated by titration by a decinormal hydrochloric acid, if large in quantity, or by “nesslerising,” if small in quantity. Crum’s method of estimating nitrates (“Foods,” p. 568) in the cases of minute stains on fabrics, &c., with a little modification, may be occasionally applicable.

IV.--Acetic Acid.

§ 90. In the ten years ending 1893 nine deaths (four males and five females) occurred in England and Wales from drinking, by mistake or design, strong acetic acid.

A few cases only have been recorded in medical literature although there have been many experiments on animals.

The symptoms in the human subject consist of pain, vomiting, and convulsions.

In animals it causes colic, paralysis of the extremities, bloody urine, and œdema of the lungs. The lethal dose for plant-eating animals is about 0·49 gramme per kilo.

There should be no difficulty in recognising acetic acid; the odour alone is, in most cases, strong and unmistakable. Traces are detected by distilling, neutralising the distillate by soda, evaporating to dryness, and treating the residue as follows:--A portion warmed with alcohol and sulphuric acid gives a smell of acetic ether. Another portion is heated in a small tube of hard glass with arsenious acid; if acetic acid is present, or an acetate, a smell of kakodyl is produced.

V.--Ammonia.

§ 91. Ammonia, (NH₃), is met with either as a vapour or gas, or as a solution of the pure gas in water.

=Properties.=--Pure ammonia gas is colourless, with a strong, irritating, pungent odour, forming white fumes of ammonic chloride, if exposed to hydric chloride vapour, and turning red moist litmus-paper strongly blue. By intense cold, or by a pressure of 6½ atmospheres at the ordinary temperature, the gas is readily liquefied; the liquid ammonia boils at 38°; its observed specific gravity is ·731; it freezes at -57·1°. Ammonia is readily absorbed by water; at 0° water will take up 1000 times its own volume, and at ordinary temperatures about 600 times its volume. Alcohol also absorbs about 10 per cent. Ammonia is a strong base, and forms a number of salts. Ammonia is one of the constant products of the putrefaction of nitrogenous substances; it exists in the atmosphere in small proportions, and in everything that contains water. Indeed, water is the only compound equal to it in its universality of diffusion. The minute quantities of ammonia thus diffused throughout nature are probably never in the free state, but combinations of ammonia with hydric nitrate, carbon dioxide, &c.

§ 92. =Uses.=[115]--A solution of ammonia in water has many applications in the arts and industries; it is used in medicine, and is an indispensable laboratory reagent.

[115] Sir B. W. Richardson has shown that ammonia possesses powerful antiseptic properties.--Brit. Med. Journal, 1862.

The officinal caustic preparations of ammonia are--ammoniæ liquor fortior (strong solution of ammonia), which should contain 32·5 per cent. of ammonia, and have a specific gravity of ·891.

Liquor ammoniæ (solution of ammonia), specific gravity ·959, and containing 10 per cent. of ammonia. There is also a liniment of ammonia, composed of olive oil, 3 parts, and ammonia, 1 part.

Spiritus Ammoniæ Fœtidus (fœtid spirit of ammonia).--A solution of assafœtida in rectified spirit and ammonia solution, 100 parts by measure, contains 10 of strong solution of ammonia.

Strong solution of ammonia is an important ingredient in the “linimentum camphoræ composita” (compound liniment of camphor), the composition of which is as follows:--camphor, 2·5 parts; oil of lavender, ·125; strong solution of ammonia, 5·0; and rectified spirit, 15 parts. Its content of strong solution of ammonia is then about 22·6 per cent. (equivalent to 7·3 of NH₃).[116]

[116] There is a common liniment for horses used in stables, and popularly known as “white oil.” It contains 1 part of ammonia, and 4 parts of olive or rape oil; not unfrequently turpentine is added. Another veterinary liniment, called “egg oil,” contains ammonia, oil of origanum, turpentine, and the yelks of eggs.

The carbonate of ammonia is also caustic; it is considered to be a compound of acid carbonate of ammonium, NH₄HCO₃, with carbamate of ammonium, NH₄NH₂CO₂. It is in the form of colourless, crystalline masses; the odour is powerfully ammoniacal; it is strongly alkaline, and the taste is acrid. It completely volatilises with heat, is soluble in water, and somewhat soluble in spirit.

The officinal preparation is the “spiritus ammoniæ aromaticus,” or aromatic spirit of ammonia. It is made by distilling in a particular way ammonic carbonate, 4 ozs.; strong solution of ammonia, 8 ozs.; rectified spirit, 120 ozs.; water, 60 ozs.; volatile oil of nutmeg, 4½ drms.; and oil of lemon, 6½ drms. Aromatic spirit of ammonia is a solution in a weak spirit of neutral carbonate, flavoured with oil of lemon and nutmeg; the specific gravity should be 0·896.

Smelling salts (sal volatile) are composed of carbonate of ammonia.

§ 93. =Statistics.=--Falck has found throughout literature notices of thirty cases of poisoning by ammonia, or some of its preparations. In two of these it was used as a poison for the purpose of murder, and in eight with suicidal intent; the remainder were all accidental. The two criminal cases were those of children, who both died. Six out of eight of the suicidal, and twelve of the twenty accidental cases also terminated fatally.

Ammonia was the cause of 64 deaths (39 male, 25 female) by accident and of 34 (18 male, 16 female) by suicide, making a total of 98 during the ten years 1883-1892 in England and Wales. At present it occupies the seventh place among poisons as a cause of accident, the ninth as a means of suicide.

§ 94. =Poisoning by Ammonia Vapour.=--Strong ammoniacal vapour is fatal to both animal and vegetable life. There are, however, but few instances of poisoning by ammonia vapour; these few cases have been, without exception, the result of accident. Two cases of death are recorded, due to an attempt to rouse epileptics from stupor, by an injudicious use of strong ammonia applied to the nostrils. In another case, when hydrocyanic acid had been taken, there was the same result. An instance is also on record of poisonous effects from the breaking of a bottle of ammonia, and the sudden evolution in this way of an enormous volume of the caustic gas. Lastly, a man employed in the manufacture of ice, by means of the liquefaction of ammonia (Carré’s process), breathed the vapour, and had a narrow escape for his life.

§ 95. =Symptoms.=--The symptoms observed in the last case may well serve as a type of what may be expected to occur after breathing ammonia vapour. The man remained from five to ten minutes in the stream of gas; he then experienced a feeling of anxiety, and a sense of constriction in the epigastrium, burning in the throat, and giddiness. He vomited. The pulse was small and frequent, the face pale, the mouth and throat strongly reddened, with increased secretion. Auscultation and percussion of the chest elicited nothing abnormal, although during the course of four days he had from time to time symptoms of suffocation, which were relieved by emetics. He recovered by the eighth day.[117]

[117] Schmidt’s Jahrbuch, 1872, i. S. 30.

In experiments on animals, very similar symptoms are produced. There is increased secretion of the eyes, nose, and mouth, with redness. The cry of cats becomes remarkably hoarse, and they generally vomit. Great difficulty in breathing and tetanic convulsions are present. When the animal is confined in a small closed chamber, death takes place in about a quarter of an hour.

On section, the bronchial tubes, to the finest ramifications, are found to be filled with a tenacious mucus, and the air passages, from the glottis throughout, reddened. The lungs are emphysematous, but have not always any special colour; the heart contains but little coagulated blood; the blood has a dark-red colour.

§ 96. The chronic effects of the gas, as shown in workmen engaged in manufactures in which the fumes of ammonia are frequent, appear to be an inflammation of the eyes and an affection of the skin. The latter is thought to be due to the ammonia uniting to form a soap with the oil of the lubricating skin glands. Some observers have also noticed deafness, and a peculiar colour of the skin of the nose and forehead, among those who work in guano manufactories. Its usual action on the body appears to be a diminution of the healthy oxidation changes, and a general lowering of bodily strength, with evident anæmia.

§ 97. =Ammonia in Solution.--Action on Plants.=--Solutions of strong ammonia, or solutions of the carbonate, act injuriously on vegetable life, while the neutral salts of ammonia are, on the contrary, excellent manures. A 30 per cent. solution of ammonic carbonate kills most plants within an hour, and it is indifferent whether the whole plant is watered with this solution, or whether it is applied only to the leaves. If, after this watering of the plant with ammonic carbonate water, the injurious salt is washed out as far as possible by distilled water, or by a weakly acidulated fluid, then the plant may recover, after having shed more or less of its leaves. These facts sufficiently explain the injurious effects noticed when urine is applied direct to plants, for urine in a very short time becomes essentially a solution of ammonic carbonate.

§ 98. =Action on Human Beings and Animal Life.=--The violence of the action of caustic solutions of ammonia almost entirely depends on the state of concentration.

The local action of the strong solution appears to be mainly the extraction of water and the saponifying of fat, making a soluble soap. On delicate tissues it has, therefore, a destructive action; but S. Samuel[118] has shown that ammonia, when applied to the unbroken epidermis, does not have the same intense action as potash or soda, nor does it coagulate albumen. Blood, whether exposed to ammonia gas, or mixed with solution of ammonia, becomes immediately dark-red; then, later, through destruction of the blood corpuscles, very dark, even black; lastly, a dirty brown-red. The oxygen is expelled, the hæmoglobin destroyed, and the blood corpuscles dissolved.

[118] Virchow’s Archiv f. path. Anat., Bd. 51, Hft. 1 u. 2, S. 41, &c., 1870.

The albumen of the blood is changed to alkali-albuminate, and the blood itself will not coagulate. A more or less fluid condition of the blood has always been noticed in the bodies of those poisoned by ammonia.

Blood exposed to ammonia, when viewed by the spectroscope, shows the spectra of alkaline hæmatin, a weak absorption-band, in the neighbourhood of D; but if the blood has been acted on for some time by ammonia, then all absorption-bands vanish. These spectra, however, are not peculiar to ammonia, the action of caustic potash or soda being similar. The muscles are excited by ammonia, the functions of the nerves are destroyed.

When a solution of strong ammonia is swallowed, there are two main effects--(1) the action of the ammonia itself on the tissues it comes into contact with, and (2) the effects of the vapour on the air-passages. There are, therefore, immediate irritation, redness, and swelling of the tongue and pharynx, a burning pain reaching from the mouth to the stomach, with vomiting, and, it may be, nervous symptoms. The saliva is notably increased. In a case reported by Fonssagrives,[119] no less than 3 litres were expelled in the twenty-four hours. Often the glands under the jaw and the lymphatics of the neck are swollen.

[119] L’Union Médicale, 1857, No. 13, p. 49, No. 22, p. 90.

Doses of from 5 to 30 grammes of the strong solution of ammonia may kill as quickly as prussic acid. In a case recorded by Christison,[120] death occurred in four minutes from a large dose, doubtless partly by suffocation. As sudden a result is also recorded by Plenk: a man, bitten by a rabid dog, took a mouthful of spirits of ammonia, and died in four minutes.

[120] Christison, 167.

If death does not occur rapidly, there may be other symptoms--dependent not upon its merely local action, but upon its more remote effects. These mainly consist in an excitation of the brain and spinal cord, and, later, convulsive movements deepening into loss of consciousness. It has been noticed that, with great relaxation of the muscular system, the patients complain of every movement causing pain. With these general symptoms added to the local injury, death may follow many days after the swallowing of the fatal dose.

Death may also occur simply from the local injury done to the throat and larynx, and the patient may linger some time. Thus, in a case quoted by Taylor,[121] in which none of the poison appears actually to have been swallowed, the man died nineteen days after taking the poison from inflammation of the throat and larynx. As with the strong acids, so with ammonia and the alkalies generally, death may also be caused many weeks and even months afterwards from the effects of contraction of the gullet, or from the impaired nutrition consequent upon the destruction, more or less, of portions of the stomach or intestinal canal.

[121] Principles of Jurisprudence, i. p. 235.

§ 99. =Post-mortem Appearances.=--In recent cases there is an intense redness of the intestinal canal, from the mouth to the stomach, and even beyond, with here and there destruction of the mucous membrane, and even perforation. A wax preparation in the museum of University College (No. 2378) shows the effects on the stomach produced by swallowing strong ammonia; it is ashen-gray in colour, and most of the mucous membrane is, as it were, dissolved away; the cardiac end is much congested.

The contents of the stomach are usually coloured with blood; the bronchial tubes and glottis are almost constantly found inflamed--even a croup-like (or diphtheritic) condition has been seen. Œdema of the glottis should also be looked for: in one case this alone seems to have accounted for death. The blood is of a clear-red colour, and fluid. A smell of ammonia may be present.

If a sufficient time has elapsed for secondary effects to take place, then there may be other appearances. Thus, in the case of a girl who, falling into a fainting fit, was treated with a draught of undiluted spirits of ammonia, and lived four weeks afterwards, the stomach (preserved in St. George’s Hospital museum, 43 b, ser. ix.) is seen to be much dilated and covered with cicatrices, and the pylorus is so contracted as hardly to admit a small bougie. It has also been noticed that there is generally a fatty degeneration of both the kidneys and liver.

It need scarcely be observed that, in such cases, no free ammonia will be found, and the question of the cause of death must necessarily be wholly medical and pathological.

§ 100. =Separation of Ammonia.=--Ammonia is separated in all cases by distillation, and if the organic or other liquid is already alkaline, it is at once placed in a retort and distilled. If neutral or acid, a little burnt magnesia may be added until the reaction is alkaline. It is generally laid down that the contents of the stomach in a putrid condition cannot be examined for ammonia, because ammonia is already present as a product of decomposition; but even under these circumstances it is possible to give an opinion whether ammonia in excess is present. For if, after carefully mixing the whole contents of the stomach, and then drying a portion and reckoning from that weight the total nitrogen (considering, for this purpose, the contents to consist wholly of albumen, which yields about 16 per cent. of nitrogen)--under these conditions, the contents of the stomach yield more than 16 per cent. of nitrogen as ammonia reckoned on the dry substance, it is tolerably certain that ammonia not derived from the food or the tissues is present.

If, also, there is a sufficient evolution of ammonia to cause white fumes, when a rod moistened with hydrochloric acid is brought near to the liquid, this is an effect never noticed with a normal decomposition, and renders the presence of extrinsic ammonia probable.

An alkaline-reacting distillate, which gives a brown colour with the “nessler” reagent, and which, when carefully neutralised with sulphuric acid, on evaporation to dryness by the careful heat of a water-bath, leaves a crystalline mass that gives a copious precipitate with platinic chloride, but is hardly at all soluble in absolute alcohol, can be no other substance than ammonia.

§ 101. =Estimation.=--Ammonia is most quickly estimated by distilling, receiving the distillate in decinormal acid, and then titrating back. It may also be estimated as the double chloride of ammonium and platinum (NH₄Cl)₂PtCl₄. The distillate is exactly neutralised by HCl, evaporated to near dryness, and an alcoholic solution of platinic chloride added in sufficient quantity to be always in slight excess, as shown by the yellow colour of the supernatant fluid. The precipitate is collected, washed with a little alcohol, dried, and weighed on a tared filter; 100 parts of the salt are equal to 7·6 of NH₃.

VI.--Caustic Potash and Soda.

§ 102. There is so little difference in the local effects produced by potash and soda respectively, that it will be convenient to treat them together.

=Potash= (=potassa caustica=).--Hydrate of potassium (KHO), atomic weight 56, specific gravity 2·1.

=Properties.=--Pure hydrate of potassium is a compact, white solid, usually met with in the form of sticks. When heated to a temperature a little under redness, it melts to a nearly colourless liquid; in this state it is intensely corrosive. It rapidly absorbs moisture from the air, and moist potash also absorbs with great avidity carbon dioxide; it is powerfully alkaline, changing red litmus to blue. It is soluble in half its weight of cold water, great heat being evolved during solution; it forms two definite hydrates--one, KHO + H₂O; the other, KHO + 2H₂O. It is sparingly soluble in ether, but is dissolved by alcohol, wood-spirit, fusel oil, and glycerin.

§ 103. =Pharmaceutical Preparations.=--Potassium hydrate, as well as the solution of potash, is officinal in all pharmacopœias. The liquor potassæ, or solution of potash, of the British Pharmacopœia, is a strongly alkaline, caustic liquid, of 1·058 specific gravity, and containing 5·84 per cent. by weight of KHO. It should, theoretically, not effervesce, when treated with an acid, but its affinity for CO₂ is so great that all solutions of potash, which have been in any way exposed to air, contain a little carbonate. Caustic sticks of potash and lime used to be officinal in the British Pharmacopœia. Filho’s caustic is still in commerce, and is made by melting together two parts of potassium hydrate and one part of lime in an iron ladle or vessel; the melted mass is now moulded by pouring it into leaden moulds. Vienna paste is composed of equal weights of potash and lime made into a paste with rectified spirit or glycerin.

§ 104. =Carbonate of Potash= (K₂CO₃ + 1½H₂O), when pure, is in the form of small white crystalline grains, alkaline in taste and reaction, and rapidly deliquescing when exposed to moist air; it gives all the chemical reactions of potassium oxide, and carbon dioxide. Carbonate of potash, under the name of salt of tartar, or potashes, is sold by oilmen for cleansing purposes. They supply it either in a fairly pure state, or as a darkish moist mass containing many impurities.

§ 105. =Bicarbonate of Potash= (KHCO₃) is in the form of large transparent rhombic prisms, and is not deliquescent. The effervescing solution of potash (liquor potassæ effervescens) consists of 30 grains of KHCO₃ in a pint of water (3·45 grms. per litre), and as much CO₂ as the water will take up under a pressure of seven atmospheres.

§ 106. =Caustic Soda--Sodium Hydrate= (NaHO).--This substance is a white solid, very similar in appearance to potassium hydrate; it absorbs moisture from the air, and afterwards carbon dioxide, becoming solid again, for the carbonate is not deliquescent. In this respect, then, there is a great difference between potash and soda, for the former is deliquescent both as hydrate and carbonate; a stick of potash in a semi-liquid state, by exposure to the air, continues liquid, although saturated with carbon dioxide. Pure sodium hydrate has a specific gravity of 2·0; it dissolves in water with evolution of heat, and the solution gives all the reactions of sodium hydrate, and absorbs carbon dioxide as readily as the corresponding solution of potash. The liquor sodæ of the B.P. should contain 4·1 per cent. of NaHO.

§ 107. =Sodæ Carbonas--Carbonate of Soda=--(Na₂CO₃10H₂O).--The pure carbonate of soda for medicinal use is in colourless and transparent rhombic octahedrons; when exposed to air, the crystals effloresce and crumble. The sodæ carbonas exsiccata, or dried carbonate of soda, is simply the ordinary carbonate, deprived of its water of crystallisation, which amounts to 62·93 per cent.

§ 108. =Bicarbonate of Soda= (NaHCO₃) occurs in the form of minute crystals, or, more commonly, as a white powder. The liquor sodæ effervescens of the B.P. is a solution of the bicarbonate, 30 grains of the salt in 20 ozs. of water (3·45 grms. per litre), the water being charged with as much carbonic acid as it will hold under a pressure of seven atmospheres. The bicarbonate of soda lozenges (trochisci sodæ bicarbonatis) contain in each lozenge 5 grains (327 mgrms.) of the bicarbonate. The carbonate of soda sold for household purposes is of two kinds--the one, “seconds,” of a dirty white colour and somewhat impure; the other, “best,” is a white mass of much greater purity. Javelle water (Eau de Javelle) is a solution of hypochlorite of soda; its action is poisonous, more from the caustic alkali than from the chlorine, and may, therefore, be here included.

§ 109. =Statistics.=--Poisoning by the fixed alkalies is not so frequent as poisoning by ammonia. Falck has collected, from medical literature, 27 cases, 2 of which were the criminal administering of Eau de Javelle, and 5 were suicidal; 22, or 81·5 per cent., died--in 1 of the cases after twenty-four hours; in the others, life was prolonged for days, weeks, or months--in 1 case for twenty-seven months. In the ten years 1883-1892, in England and Wales, there were 27 deaths from poisoning by the fixed alkalies; 2 were suicidal (1 from potash, the other from soda); the remaining 25 were due to accident; of these, 7 (3 males and 4 females) were from caustic soda, and 18 (8 males and 10 females) from caustic potash.

§ 110. =Effects on Animal and Vegetable Life.=--The fixed alkalies destroy all vegetable life, if applied in strong solution or in substance, by dehydrating and dissolving the tissues. The effects on animal tissues are, in part, due also to the affinity of the alkalies for water. They extract water from the tissues with which they come in contact, and also attack the albuminous constituents, forming alkali-albuminate, which swells on the addition of water, and, in a large quantity, even dissolves. Cartilaginous and horny tissues are also acted upon, and strong alkalies will dissolve hair, silk, &c. The action of the alkali is by no means restricted to the part first touched, but has a remarkable faculty of spreading in all directions.

§ 111. =Local Effects.=--The effects of strong alkali applied to the epidermis are similar to, but not identical with, those produced by strong acids. S. Samuel[122] has studied this experimentally on the ear of the rabbit; a drop of a strong solution of caustic alkali, placed on the ear of a white rabbit, caused stasis in the arteries and veins, with first a greenish, then a black colour of the blood; the epidermis was bleached, the hair loosened, and there quickly followed a greenish coloration on the back of the ear, opposite to the place of application. Around the burned spot appeared a circle of anastomising vessels, a blister rose, and a slough separated in a few days. The whole thickness of the ear was coloured yellowish-green, and, later, the spot became of a rusty brown.

[122] Virchow’s Archiv. f. path. Anat., Bd. 51, Hft. 1 u. 2, 1870.

§ 112. =Symptoms.=--The symptoms observed when a person has swallowed a dangerous dose of caustic (fixed) alkali are very similar to those noticed with ammonia, with the important exception that there is no respiratory trouble, unless the liquid has come into contact with the glottis; nor has there been hitherto remarked the rapid death which has taken place in a few ammonia poisonings, the shortest time hitherto recorded being three hours, as related by Taylor, in a case in which a boy had swallowed 3 ozs. of a strong solution of carbonate of potash.

There is instant pain, extending from the mouth to the stomach, and a persistent and unpleasant taste; if the individual is not a determined suicide, and the poison (as is mostly the case) has been taken accidentally, the liquid is immediately ejected as much as possible, and water, or other liquid at hand, drunk freely. Shock may at once occur, and the patient die from collapse; but this, even with frightful destruction of tissue, appears to be rare. Vomiting supervenes; what is ejected is strongly alkaline, and streaked with blood, and has a soapy, frothy appearance. There may be diarrhœa, great tenderness of the abdomen, and quick pulse and fever. With caustic potash, there may be also noticed its toxic effects (apart from local action) on the heart; the pulse, in that case, is slow and weak, and loss of consciousness and convulsions are not uncommon. If the collapse and after-inflammation are recovered from, then, as in the case of the mineral acids, there is all the horrid sequence of symptoms pointing to contractions and strictures of the gullet or pylorus, and the subsequent dyspepsia, difficulty of swallowing, and not unfrequently actual starvation.

§ 113. =Post-mortem Appearances.=--In cases of recent poisoning, spots on the cheeks, lips, clothing, &c., giving evidence of the contact of the alkali, should be looked for; but this evidence, in the case of persons who have lived a few days, may be wanting. The mucous membrane of the mouth, throat, gullet, and stomach is generally more or less white--here and there denuded, and will be found in various stages of inflammation and erosion, according to the amount taken, and the concentration of the alkali. Where there is erosion, the base of the eroded parts is not brown-yellow, but, as a rule, pale red. The gullet is most affected at its lower part, and it is this part which is mostly subject to stricture. Thus Böhm[123] found that in 18 cases of contraction of the gullet, collected by him, 10 of the 18 showed the contraction at the lower third.

[123] Centralblatt für die Med. Wiss., 1874.

The changes which the stomach may present if the patient has lived some time, are well illustrated by a preparation in St. George’s museum (43 a. 264, ser. ix.). It is the stomach of a woman, aged 44, who had swallowed a concentrated solution of carbonate of potash. She vomited immediately after taking it, and lived about two months, during the latter part of which she had to be nourished by injections. She died mainly from starvation. The gullet in its lower part is seen to be much contracted, its lining membrane destroyed, and the muscular coats exposed. The coats of the stomach are thickened, but what chiefly arrests the attention is a dense cicatrix at the pylorus, with an aperture so small as only to admit a probe.

The colour of the stomach is generally bright red, but in that of a child, preserved in Guy’s Hospital museum (No. 1798²⁴), the mucous membrane is obliterated, the rugæ destroyed, and a dark-brown stain is a noticeable feature. The stomach is not, however, necessarily affected. In a preparation in the same museum (No. 1798²⁰) the mucous membrane of the stomach of a child who swallowed soap-lees is seen to be almost healthy, but the gullet is much discoloured. The action on the blood is to change it into a gelatinous mass; the blood corpuscles are destroyed, and the whole colour becomes of a dirty blackish-red; the spectroscopic appearances are identical with those already described (see p. 114).

The question as to the effects of chronic poisoning by the alkalies or their carbonates may arise. Little or nothing is, however, known of the action of considerable quantities of alkalies taken daily. In a case related by Dr. Tunstall,[124] a man for eighteen years had taken daily 2 ozs. of bicarbonate of soda for the purpose of relieving indigestion. He died suddenly, and the stomach was found extensively diseased; but since the man, before taking the alkali, had complained of pain, &c., it is hardly well, from this one case, to draw any conclusion.

[124] Med. Times, Nov. 30, 1850, p. 564.

It is important to observe that the contents of the stomach may be acid, although the death has been produced by caustic alkali. A child, aged 4, drank from a cup some 14 per cent. soda lye. He vomited frequently, and died in fifteen hours. The stomach contained 80 c.c. of sour-smelling turbid fluid, the reaction of which was acid. There were hæmorrhagic patches in the stomach, and signs of catarrhal inflammation; there was also a similarly inflamed condition of the duodenum.[125]

[125] Lesser, Atlas d. gericht. Med., Tafel ii.

§ 114. =Chemical Analysis.=--The tests for potassium or sodium are too well known to need more than enumeration. The intense yellow flame produced when a sodium salt is submitted to a Bunsen flame, and the bright sodium-line at D when viewed by the spectroscope, is a delicate test; while potassium gives a dull red band in the red, and a faint but very distinct line in the violet. Potassium salts are precipitated by tartaric acid, while sodium salts do not yield this precipitate; potassium salts also give a precipitate with platinic chloride insoluble in strong alcohol, while the compound salt with sodium is rapidly dissolved by alcohol or water. This fact is utilised in the separation and estimation of the two alkalies.

§ 115. =Estimation of the Fixed Alkalies.=--To detect a fixed alkali in the contents of the stomach, a convenient process is to proceed by dialysis, and after twenty-four hours, to concentrate the outer liquid by boiling, and then, if it is not too much coloured, to titrate directly with a decinormal sulphuric acid. After exact neutralisation, the liquid is evaporated to dryness, carbonised, the alkaline salts lixiviated out with water, the sulphuric acid exactly precipitated by baric chloride, and then, after separation of the sulphate, the liquid treated with milk of lime. The filtrate is treated with a current of CO₂ gas, boiled, and any precipitate filtered off; the final filtrate will contain only alkalies. The liquid may now be evaporated to dryness with either hydrochloric or sulphuric acids, and the total alkalies weighed as sulphates or chlorides. Should it be desirable to know exactly the proportion of potassium to sodium, it is best to convert the alkalies into chlorides--dry gently, ignite, and weigh; then dissolve in the least possible quantity of water, and precipitate by platinic chloride, which should be added so as to be a little in excess, but not much. The liquid thus treated is evaporated nearly to dryness, and then extracted with alcohol of 80 per cent., which dissolves out any of the double chloride of platinum and sodium. Finally, the precipitate is collected on a tared filter and weighed, after drying at 100°. In this way the analyst both distinguishes between the salts of sodium and potassium, and estimates the relative quantities of each. It is hardly necessary to observe that, if the double chloride is wholly soluble in water or alcohol, sodium alone is present. This, however, will never occur in operating on organic tissues and fluids, for both alkalies are invariably present. A correction must be made when complex organic fluids are in this way treated for alkalies which may be naturally in the fluid. Here the analyst will be guided by his preliminary titration, which gives the total free alkalinity. In cases where the alkali has been neutralised by acids, of course no free alkali will be found, but the corresponding salt.

VII.--Neutral Sodium, Potassium, and Ammonium Salts.

§ 116. The neutral salts of the alkalies are poisonous, if administered in sufficient doses, and the poisonous effect of the sulphate, chloride, bromide, iodide, tartrate, and citrate appears to depend on the specific action of the alkali metal, rather than on the acid, or halogen in combination. According to the researches of Dr. Ringer and Dr. Harrington Sainsbury,[126] with regard to the relative toxicity of the three, as shown by their effect on the heart of a frog--first, the potassium salts were found to exert the most poisonous action, next come the ammonium, and, lastly, the sodium salts. The highest estimate would be that sodium salts are only one-tenth as poisonous as those of ammonium or potassium; the lowest, that the sodium salts are one-fifth: although the experiments mainly throw light upon the action of the alkalies on one organ only, yet the indications obtained probably hold good for the organism as a whole, and are pretty well borne out by clinical experience.

[126] Lancet, June 24, 1882.

There appear to be four cases on record of poisoning by the above neutral salts; none of them belong to recent times, but lie between the years 1837-1856. Hence, the main knowledge which we possess of the poisonous action of the potassium salts is derived from experiments on animals.

§ 117. =Sodium Salts.=--Common salt in such enormous quantity as half a pound to a pound has destroyed human life, but these cases are so exceptional that the poisonous action of sodium salts is of scientific rather than practical interest.

§ 118. =Potassium Salts.=--Leaving for future consideration the nitrate and the chlorate of potassium, potassic sulphate and tartrate are substances which have destroyed human life.

=Potassic Sulphate= (K₂SO₄) is in the form of colourless rhombic crystals, of bitter saline taste. It is soluble in 10 parts of water.

=Hydropotassic Tartrate= (KHC₄H₄O₆), when pure, is in the form of rhombic crystals, tasting feebly acid. It is soluble in 210 parts of water at 17°.

§ 119. =Action on the Frog’s Heart.=--Both excitability and contractility are affected to a powerful degree. There is a remarkable slowing of the pulsations, irregularity, and, lastly, cessation of pulsation altogether.

§ 120. =Action on Warm-Blooded Animals.=--If a sufficient quantity of a solution of a potassic salt is injected into the blood-vessels of an animal, there is almost immediate death from arrest of the heart’s action. Smaller doses, subcutaneously applied, produce slowing of the pulse, dyspnœa, and convulsions, ending in death. Small doses produce a transitory diminution of the force of arterial pressure, which quickly passes, and the blood-pressure rises. There is at first, for a few seconds, increase in the number of pulsations, but later a remarkable slowing of the pulse. The rise in the blood-pressure occurs even after section of the spinal cord. Somewhat larger doses cause rapid lowering of the blood-pressure, and apparent cessation of the heart’s action; but if the thorax be then opened, the heart is seen to be contracting regularly, making some 120-160 rhythmic movements in the minute. If the respiration be now artificially maintained, and suitable pressure made on the walls of the chest, so as to empty the heart of blood, the blood-pressure quickly rises, and natural respiration may follow. An animal which lay thirty-six minutes apparently dead was in this way brought to life again (Böhm). The action of the salts of potassium on the blood is the same as that of sodium salts. The blood is coloured a brighter red, and the form of the corpuscles changed; they become shrivelled through loss of water. Voluntary muscle loses quickly its contractility when a solution of potash is injected into its vessels. Nerves also, when treated with a 1 per cent. solution of potassic chloride, become inexcitable.

§ 121. =Elimination.=--The potassium salts appear to leave the body through the kidneys, but are excreted much more slowly than the corresponding sodium salts. Thus, after injection of 4 grms. of potassic chloride--in the first sixteen hours ·748 grm. of KCl was excreted in the urine, and in the following twenty-four hours 2·677 grms.

§ 122. =Nitrate of Potash= (KNO₃).--Pure potassic nitrate crystallises in large anhydrous hexagonal prisms with dihedral summits; it does not absorb water, and does not deliquesce. Its fusing point is about 340°; when melted it forms a transparent liquid, and loses a little of its oxygen, but this is for the most part retained by the liquid given off when the salt solidifies. At a red-heat it evolves oxygen, and is reduced first to nitrite; if the heat is continued, potassic oxide remains. The specific gravity of the fused salt is 2·06. It is not very soluble in cold water, 100 parts dissolving only 26 at 15·6°; but boiling water dissolves it freely, 100 parts dissolving 240 of the salt.

A solution of nitrate of potash, when treated with a zinc couple (see “Foods,” p. 566), is decomposed, the nitrate being first reduced to nitrite, as shown by its striking a red colour with metaphenylene-diamine, and then the nitrite farther decomposing, and ammonia appearing in the liquid. If the solution is alkalised, and treated with aluminium foil, hydrogen is evolved, and the same effect produced. As with all nitrates, potassic nitrate, on being heated in a test-tube with a little water, some copper filings, and sulphuric acid, evolves red fumes of nitric peroxide.

§ 123. =Statistics.=--Potassic nitrate, under the popular name of “nitre,” is a very common domestic remedy, and is also largely used as a medicine for cattle. There appear to be twenty cases of potassic nitrate poisoning on record--of these, eight were caused by the salts having been accidentally mistaken for magnesic sulphate, sodic sulphate, or other purgative salt; two cases were due to a similar mistake for common salt. In one instance, the nitrate was used in strong solution as an enema, but most of the cases were due to the taking of too large an internal dose.

§ 124. =Uses in the Arts=, &c.--Both sodic and potassic nitrates are called “nitre” by the public indiscriminately. Sodic nitrate is imported in large quantities from the rainless districts of Peru as a manure. Potassic nitrate is much used in the manufacture of gunpowder, in the preservation of animal substances, in the manufacture of gun cotton, of sulphuric and nitric acids, &c. The maximum medicinal dose of potassium nitrate is usually stated to be 30 grains (1·9 grm.).

§ 125. =Action of Nitrates of Sodium and Potassium.=--Both of these salts are poisonous. Potassic nitrate has been taken with fatal result by man; the poisonous nature of sodic nitrate is established by experiments on animals. The action of the nitrates of the alkalies is separated from that of the other neutral salts of potassium, &c., because in this case the toxic action of the combined nitric acid plays no insignificant part. Large doses, 3-5 grms. (46·3-77·2 grains), of potassic nitrate cause considerable uneasiness in the stomach and bowels; the digestion is disturbed; there may be vomiting and diarrhœa, and there is generally present a desire to urinate frequently. Still larger doses, 15-30 grms. (231·5-463 grains), rapidly produce all the symptoms of acute gastro-enteritis--great pain, frequent vomiting (the ejected matters being often bloody), with irregularity and slowing of the pulse; weakness, cold sweats, painful cramps in single muscles (especially in the calves of the legs); and, later, convulsions, aphonia, quick collapse, and death.

In the case of a pregnant woman, a handful of “nitre” taken in mistake for Glauber’s salts produced abortion after half-an-hour. The woman recovered. Sodic nitrate subcutaneously applied to frogs kills them, in doses of ·026 grm. (·4 grain), in about two hours; there are fibrillar twitchings of single groups of muscles and narcosis. The heart dies last, but after ceasing to beat may, by a stimulus, be made again to contract. Rabbits, poisoned similarly by sodic nitrate, exhibit also narcotic symptoms; they lose consciousness, lie upon their side, and respond only to the sharpest stimuli. The breathing, as well as the heart, is “slowed,” and death follows after a few spasmodic inspirations.

=Sodic nitrite= was found by Barth to be a more powerful poison, less than 6 mgrms. (·1 grain) being sufficient to kill a rabbit of 455·5 grms. (7028 grains) weight, when subcutaneously injected. The symptoms were very similar to those produced by the nitrate.

§ 126. The post-mortem appearances from potassic nitrate are as follows:--An inflamed condition of the stomach, with the mucous membrane dark in colour, and readily tearing; the contents of the stomach are often mixed with blood. In a case related by Orfila, there was even a small perforation by a large dose of potassic nitrate, and a remarkable preservation of the body was noted.

It is believed that the action of the nitrates is to be partly explained by a reduction to nitrites, circulating in the blood as such. To detect nitrites in the blood, the best method is to place the blood in a dialyser, the outer liquid being alcohol. The alcoholic solution may be evaporated to dryness, extracted with water, and then tested by metaphenylene-diamine.

§ 127. =Potassic Chlorate= (KClO₃).--Potassic chlorate is in the form of colourless, tabular crystals with four or six sides. About 6 parts of the salt are dissolved by 100 of water at 15°, the solubility increasing with the temperature, so that at 100° nearly 60 parts dissolve; if strong sulphuric acid be dropped on the crystals, peroxide of chlorine is evolved; when rubbed with sulphur in a mortar, potassic chlorate detonates. When the salt is heated strongly, it first melts, and then decomposes, yielding oxygen gas, and is transformed into the perchlorate. If the heat is continued, this also is decomposed, and the final result is potassic chloride.

§ 128. =Uses.=--Potassic chlorate is largely used as an oxidiser in calico printing, and in dyeing, especially in the preparation of aniline black. A considerable quantity is consumed in the manufacture of lucifer matches and fireworks; it is also a convenient source of oxygen. Detonators for exploding dynamite are mixtures of fulminate of mercury and potassic chlorate. It is employed as a medicine both as an application to inflamed mucous membranes, and for internal administration; about 2000 tons of the salt for these various purposes are manufactured yearly in the United Kingdom.

§ 129. =Poisonous Properties.=--The facility with which potassic chlorate parts with its oxygen by the aid of heat, led to its very extensive employment in medicine. No drug, indeed, has been given more recklessly, or on a less scientific basis. Wherever there were sloughing wounds, low fevers, and malignant sore throats, especially those of a diphtheritic character, the practitioner administered potassic chlorate in colossal doses. If the patient died, it was ascribed to the malignity of the disease--if he recovered, to the oxygen of the salt; and it is possible, from the light which of recent years has been thrown on the action of potassic chlorate, that its too reckless use has led to many unrecorded accidents.

§ 130. =Experiments on Animals.=--F. Marchand[127] has studied the effects of potassic chlorate on animals, and on blood. If either potassic chlorate or sodic chlorate is mixed with fresh blood, it shows after a little while peculiar changes; the clear red colour at first produced passes, within a few hours, into a dark red-brown, which gradually becomes pure brown. This change is produced by a 1 per cent. solution, in from fifteen to sixteen hours; and a 4 per cent. solution at 15° destroys every trace of oxyhæmoglobin within four hours. Soon the blood takes a syrupy consistence, and, with a 2-4 per cent. solution of the salt, passes into a jelly-like mass. The jelly has much permanence, and resists putrefactive changes for a long time.

[127] Virchow’s Archiv. f. path. Anat., Bd. 77, Hft. 3, S. 455, 1879.

Marchand fed a dog of 17 kilos. in weight with 5 grms. of potassic chlorate for a week. As there were no apparent symptoms, the dose was doubled for two days; and as there was still no visible effect, lastly, 50 grms. of sodic chlorate were given in 5 doses. In the following night the dog died. The blood was found after death to be of a sepia-brown colour, and remained unaltered when exposed to the air. The organs were generally of an unnatural brown colour; the spleen was enormously enlarged; the kidneys were swollen, and of a dark chocolate brown--on section, almost black-brown, the colour being nearly equal, both in the substance and in the capsule. A microscopical examination of the kidney showed the canaliculi to be filled with brownish cylinders consisting of altered blood. A spectroscopic examination of the blood showed weak hæmoglobin bands, and a narrow band in the red. With farther dilution, the hæmoglobin bands vanished, but the band in the red remained. The diluted blood, when exposed to the light, still remained of a coffee-brown colour; and on shaking, a white-brown froth was produced on the surface.

A second experiment in which a hound of from 7-8 kilos. in weight was given 3-5 grm. doses of potassic chlorate in sixteen hours, and killed by bleeding seven to eight hours after the last dose, showed very similar appearances. The kidneys were intensely congested, and the peculiar brown colour was noticeable.

§ 131. =Effects on Man.=--I find in literature thirty-nine cases recorded, in which poisonous symptoms were directly ascribed to the action of chlorate of potassium; twenty-eight of these terminated fatally. A quadruple instance of poisoning, recorded by Brouardel and L’Hôte,[128] illustrates many of the points relative to the time at which the symptoms may be expected to commence, and the general aspect of potassic chlorate poisoning. The “supérieure” of a religious institution was in the habit of giving, for charitable purposes, a potion containing 15 grms. (3·8 drms.) of potassic chlorate, dissolved in 360 c.c. (about 12½ ozs.) of a vegetable infusion.

[128] Annales d’Hygiène publique, 1881, p. 232.

This potion was administered to four children--viz., David, aged 2½; Cousin, aged 3½; Salmont, 2½; and Guérin, 2½. David took the whole in two and a half hours, the symptoms commenced after the potion was finished, and the child died five and a half hours after taking the first dose; there were vomiting and diarrhœa. Cousin took the medicine in seven hours; the symptoms also commenced after the last spoonful, and the death took place eight and a half hours from the first spoonful. The symptoms were mainly those of great depression; the lips were blue, the pulse feeble, there was no vomiting, no diarrhœa. Salmont took the medicine in nine hours, and died in twelve. There was some diarrhœa, the stools were of a green colour. Guérin took the whole in two hours, the symptoms commenced in four hours; the lips were very pale, the gums blue. Death took place in four days.

There was an autopsy in the case of David only. The stomach showed a large ecchymosis on its mucous membrane, as if it had been burnt by an acid; the spleen was gorged with blood, and its tissue friable; the kidneys do not seem to have been thoroughly examined, but are said to have been tumefied. Potassic chlorate was discovered by dialysis. In the cases of the children just detailed, the symptoms appear to be a mixture of the depressing action of the potassium, and irritant action of the chlorate.

§ 132. In adults, the main symptoms are those of nephritis, and the fatal dose for an adult is somewhere about an ounce (28·3 grms.), but half this quantity would probably be dangerous, especially if given to a person who had congestion or disease of the kidneys.

Dr. Jacobi[129] gives the following cases.

[129] Amer. Med. Times, 1860.

Dr. Fountain in 1858, experimenting on himself, took 29·2 grms. (8·7 drms.) of potassic chlorate; he died on the seventh day from nephritis. A young lady swallowed 30 grms. (8·5 drms.), when using it as a gargle; she died in a few days from nephritis. A man, thirty years of age, died in four days after having taken 48 grms. (12·3 drms.) of sodic chlorate in six hours. The shortest time in which I can find the salt to have been fatal, is a case related by Dr. Manouvriez, in which a woman took 45 grms., and died in five hours. The smallest dose which has proved fatal is one in which an infant three years old was killed by 3 grms. (46·3 grains).

Jacobi considers that the maximum dose to be given in divided doses during the twenty-four hours, to infants under three, should be from 1-1·5 grm. (15·4-23·1 grains), to children from three years old, up to 2 grms. (30·8 grains); and adults from 6-8 grms. (92·6-123·4 grains).

§ 133. =Elimination.=--Potassic chlorate is quickly absorbed by mucous membranes, and by the inflamed skin, and rapidly separated from the body by the action of the kidneys. Wöhler, as early as 1824, recognised that it in great part passed out of the body unchanged, and, lately, Isambert, in conjunction with Hirne,[130] making quantitative estimations, recovered from the urine no less than 95 per cent. of the ingested salts. Otto Hehner has also made several auto-experiments, and taking 2½ drms., found that it could be detected in the urine an hour and a half afterwards. At that time 17·23 per cent. of the salt had been excreted, and, by the end of eleven hours, 93·8 per cent. was recovered. It is then difficult to believe that the salt gives any oxygen to the tissues, for though it is true that in all the investigations a small percentage remains to be accounted for, and also that Binz,[131] making experiments by mixing solutions of potassic chlorate with moist organic substances, such as pus, yeast, fibrin, &c., has declared that, at a blood heat the chlorate is rapidly reduced, and is no longer recognisable as chlorate--yet it may be affirmed that potassic chlorate is recovered from the urine as completely as anything which is ever excreted by the body, and that deductions drawn from the changes undergone by the salt in solutions of fibrin, &c., have only an indirect bearing on the question.

[130] Gaz. Méd. de Paris, 1875, Nro. 17, 35, 41, 43.

[131] Berlin klin. Wochenschr., xi. 10, S. 119, 1874.

§ 134. The essential action of potassic chlorate seems to be that it causes a peculiar change in the blood, acting on the colouring matter and corpuscles; the latter lose their property as oxygen carriers; the hæmoglobin is in part destroyed; the corpuscles dissolved. The decomposed and altered blood-corpuscles are crowded into the kidneys, spleen, &c.; they block up the uriniferous canaliculi, and thus the organs present the curious colouring seen after death, and the kidneys become inflamed.

Detection and Estimation of Potassic Chlorate.

§ 135. Organic fluids are best submitted to dialysis; the dialysed fluid should then be concentrated and qualitative tests applied. One of the best tests for the presence of a chlorate is, without doubt, that recommended by Fresenius. The fluid to be tested is acidulated with a few drops of sulphuric acid; sulphate of indigo added sufficient to colour the solution blue, and finally a few drops of sulphurous acid. In presence of potassic or sodic chlorate, the blue colour immediately vanishes. This method is capable of detecting 1 part in 128,000; provided the solution is not originally coloured, and but little organic matter is present.

The urine can be examined direct, but if it contain albumen, the blue colour may disappear and yet chlorate be present; if too much sulphurous acid be also added, the test may give erroneous results. These are but trivial objections, however, for if the analyst obtains a response to the test, he will naturally confirm or disprove it by the following process:--

The liquid under examination, organic or otherwise, is divided into two equal parts. In the one, all the chlorine present is precipitated as chloride by silver nitrate in the usual way, and the chloride of silver collected and weighed. In the other, the liquid is evaporated to dryness and well charred by a dull red heat, the ash dissolved in weak nitric acid, and the chlorides estimated as in the first case. If chlorates were present, there will be a difference between the two estimations, proportionate to the amount of chlorates which have been converted into chlorides by the carbonisation, and the first silver chloride subtracted from the second will give an argentic chloride which is to be referred to chlorate. In this way also the amount present may be quantitatively estimated, 100 parts of silver chloride equalling 85·4 of potassic chlorate.

Toxicological Detection of Alkali Salts.

(See also ante, p. 121.)

§ 136. Sodium, in combination, especially with chlorine, and also with sulphuric, carbonic, and phosphoric acids, is found in the plasma of the blood, in the urinary secretion, in the pancreatic juice, in human bile, and in serous transudations, &c. Potassium, in combination, is especially found in the red blood-corpuscles, in the muscles, in the nervous tissues, and in milk. Ammonia, in combination with acids, is naturally found in the stomach, in the contents of the intestine; it is also a natural constituent of the blood in small traces, and in a corpse is copiously evolved from putrefactive changes.

It hence follows, that mere qualitative tests for these elements in the tissues or fluids of the body are of not the slightest use, for they are always present during the life of the healthiest individual, and can be found after death in persons dying from any malady whatever. To establish the fact of a person having taken an unusual dose of any of the alkali salts, by simply chemical evidence, it must be proved that the alkalies are present in unusual quantities or in an abnormal state of combination.

In cases of rapid death, caused by sodic or potassic salts, they will be found in such quantity in the contents of the stomach, or in matters vomited, that there will probably be no difficulty in coming to a direct conclusion; but if some time has elapsed, the analyst may not find a sufficient ground for giving a decided judgment, the excretion of the alkali salts being very rapid.

In most cases, it will be well to proceed as follows:--The contents of the stomach are, if necessary, diluted with distilled water, and divided into three parts, one of which is submitted to dialysis, and then the dialysed liquid evaporated to a small bulk and examined qualitatively, in order to ascertain whether a large amount of the alkaline salts is present, and in what form. In this way, the presence or absence of nitrate of potassium or sodium may be proved, or the iodide, bromide, sulphate, and chlorate detected.

To find, in this way, nitrate of potassium, a coarse test is preferable to the finer tests dependent upon conversion of the nitrate into nitrites or into ammonia, for these tests are so delicate, that nitrates may be detected in traces; whereas, in this examination, to find traces is of no value. Hence, the old-fashioned test of treating the concentrated liquid in a test-tube with copper filings and then with sulphuric acid, and looking for the red fumes, is best, and will act very well, even should, as is commonly the case, some organic matters have passed through the dialyser.

Chlorates are indicated if the liquid is divided into two parts and tested in the manner recommended at p. 127. If present in any quantity, chlorates or nitrates may be indicated by the brilliant combustion of the organic matter when heated to redness, as also by the action of strong sulphuric acid on the solid substances--in the one case, yellow vapours of peroxide of chlorine being evolved--in the other, the red fumes already mentioned of nitric peroxide.

With regard to a substance such as the hydro-potassic tartrate, its insolubility in water renders it not easy of detection by dialysis; but its very insolubility will aid the analyst, for the contents of the stomach may be treated with water, and thus all soluble salts of the alkalies extracted. On now microscopically examining the insoluble residue, crystals of bitartrate, if present, will be readily seen. They may be picked up on a clean platinum wire and heated to redness in a Bunsen flame, and spectroscopically examined. After heating, the melted mass will have an alkaline reaction, and give a precipitate with platinic chloride. All other organic salts of potassium are soluble, and a white crystal giving such reaction must be hydro-potassic tartrate.

=Ammonium Salts.=--If the body is fresh, and yet the salts of ammonium present in large amount, it is safe to conclude that they have an external origin; but there might be some considerable difficulty in criminal poisoning by a neutral salt of ammonium, and search for it in a highly putrid corpse. Probably, in such an exceptional case, there would be other evidence. With regard to the quantitative separation and estimation of the fixed alkalies in the ash of organic substances, the reader is referred to the processes given in “Foods,” p. 99, et seq., and in the present work, p. 121.

PART V.--MORE OR LESS VOLATILE POISONOUS SUBSTANCES CAPABLE OF BEING SEPARATED BY DISTILLATION FROM NEUTRAL OR ACID LIQUIDS.

HYDROCARBONS--CAMPHOR--ALCOHOL--AMYL NITRITE--ETHER--CHLOROFORM AND OTHER ANÆSTHETICS--CHLORAL--CARBON DISULPHIDE--CARBOLIC ACID--NITRO-BENZENE--PRUSSIC ACID--PHOSPHORUS.

I.--Hydrocarbons.

1. PETROLEUM.

§ 137. Petroleum is a general term for a mixture of hydrocarbons of the paraffin series, which are found naturally in certain parts of the world, and are in commerce under liquid and solid forms of various density. Crude petroleum is not imported into England, the original substance having previously undergone more or less rectification. The lighter and more volatile portions are known under the name of cymogene, rhigolene, gasolene, and naphtha.

§ 138. =Cymogene= has a specific gravity of ·590, and boils at 0°. It has been employed in refrigerating machines. It appears to consist chiefly of butane (C₄H₁₀).

§ 139. =Rhigolene= is now used in medicine in the form of spray to produce local anæsthesia. It boils at 18°, and has a density of ·650.

§ 140. =Gasolene= has a density of ·680-·688; it has received technical applications in the “naphthalising” of air and gas.

§ 141. =Benzoline= (=mineral naphtha=, =petroleum naphtha=, =petroleum spirit=, =petroleum ether=) is a mixture of the lighter series of hydro-carbons; the greater part consists of heptane, and there is also a considerable quantity of pentane (C₇H₁₆) present. The specific gravity varies from ·69 to ·74. It is very inflammable, and is used in sponge lamps, and also as a solvent for gutta-percha, naphthalene, paraffin, wax, and many other bodies. By the practical chemist it is much employed.

The similarity of the terms benzoline and benzene has caused benzoline to be often confused with benzol or benzene, the leading constituent of coal-tar naphtha (C₆H₆). Mr Allen[132] gives in the following table a summary of the chief points of distinction, both between petroleum naphtha, shale naphtha, and coal-tar naphtha. The table is founded upon the examination of particular samples, and commercial samples may present a few minor deviations.

[132] Commercial Organic Analysis, vol. ii. p. 31.

TABLE OF THE VARIETIES OF NAPHTHA.

+---------------------+----------------------+----------------------+ | Petroleum Naphtha. | Shale Naphtha. | Coal-tar Naphtha. | +---------------------+----------------------+----------------------+ |Contains at least 75 |Contains at least 60 |Consists almost wholly| |per cent. of heptane,|to 70 per cent. of |of benzene, C₆H₆, and | |C₇H₁₆, and other |heptylene, C₇H₁₄, and |other homologous | |hydrocarbons of the |other hydrocarbons of |hydrocarbons, with a | |marsh gas or paraffin|the olefin series; the|small percentage of | |series; the remainder|remainder paraffins. |light hydrocarbons in | |apparently olefins, |No trace of benzene or|some samples. | |C_{n}H_{2n}, with |its homologues. | | |distinct traces of | | | |benzene and its | | | |homologues. | | | | | | | |Specific gravity at |Specific gravity at |Specific gravity ·876.| |15°, ·600. |15°, ·718. | | | | | | |Distils between 65° |Distils between 65° |Distils between 80° | |and 100°. |and 100°. |and 120°. | | | | | |Dissolves coal-tar |Behaves similarly to |Readily dissolves | |pitch, but slightly; |petroleum naphtha with|pitch, forming a deep | |liquid, but little |regard to the solution|brown solution. | |coloured even after |of pitch. | | |prolonged contact. | | | | | | | |On shaking three |When treated with |The liquids form a | |measures of the |fused carbolic acid |homogeneous mixture | |sample with one |crystals, the liquids |when treated with | |measure of fused |mix perfectly. |fused carbolic acid | |crystals of absolute | |crystals. | |carbolic acid, no | | | |solution. Liquids not| | | |miscible. | | | | | | | |Combines with 10 per |Combines with upwards |Combines slowly with | |cent. of its weight |of 90 per cent. of its|30-40 per cent. of its| |of bromine in the |weight of bromine. |weight of bromine. | |cold. | | | +---------------------+----------------------+----------------------+

§ 142. =Paraffin Oil= (or =kerosine, mineral oil, photogen=, &c.) is the chief product resulting from the distillation of American petroleum--the usual specific gravity is about ·802--it is a mixture of hydrocarbons of the paraffin series. It should be free from the more volatile constituents, and hence should not take fire when a flame is applied near the surface of the cold liquid.

§ 143. =Effects of Petroleum.=--Since we have here to deal with a commercial substance of such different degrees of purity, and various samples of which are composed of such various proportions of different hydrocarbons, its action can only be stated in very general terms. Eulenberg[133] has experimented with the lighter products obtained from the distillation of Canadian petroleum. This contained sulphur products, and was extremely poisonous, the vapour killing a rabbit in a short time, with previous insensibility and convulsions. The autopsy showed a thin extravasation of blood on the surface of each of the bulbi, much coagulated blood in the heart, congested lungs, and a bloody mucus covering the tracheal mucous membrane. An experiment made on a cat with the lighter petroleum (which had no excess of sulphur) in the state of vapour, showed that it was an anæsthetic, the anæsthesia being accompanied by convulsions, which towards the end were tetanic and violent. The evaporation of 1·5 grm. in a close chamber killed the animal in three hours. The lungs were found congested, but little else was remarkable. Much petroleum vapour is breathed in certain factories, especially those in which petroleum is refined.[134] From this cause there have been rather frequent toxic symptoms among the workmen. Eulenberg[135] describes the symptoms as follows:--A person, after breathing an overdose of the vapour, becomes very pale, the lips are livid, the respiration slow, the heart’s action weak and scarcely to be felt. If he does not immediately go into the open air away from the poisonous vapour, these symptoms may pass on to insensibility, convulsions, and death. It often occasions a condition of the voluntary muscles similar to that induced by drunkenness, and on recovery the patient is troubled by singing in the ears and noises in the head. The smell and taste of the poison may remain for a long time.

[133] Gewerbe-Hygiene.

[134] The vapour most likely to rise at the ordinary temperature, and mix with the atmosphere, is that of the lighter series, from cymogene to benzoline.

[135] Op. cit.

§ 144. Poisoning by taking light petroleum into the stomach is not common. In a case recorded by Taylor,[136] a woman, for the purpose of suicide, swallowed a pint of petroleum, There followed a slight pain in the stomach, and a little febrile disturbance, and a powerful smell of petroleum remained about the body for six days; but she completely recovered. In August 1870 a sea-captain drank a quantity of paraffin, that is, lighting petroleum, and died in a few hours in an unconscious state. A child, 2 years old, was brought to King’s College Hospital within ten minutes after taking a teaspoonful of paraffin. It was semi-comatose and pale, with contracted pupils; there was no vomiting or purging. Emetics of sulphate of zinc were administered, and the child recovered in twenty-four hours. In another case treated at the same hospital, a child had swallowed an unknown quantity of paraffin. It fell into a comatose state, which simulated tubercular meningitis, and lasted for nearly three weeks.[137] In a case recorded by Mr Robert Smith,[138] a child, 4 years of age, had swallowed an unknown quantity of paraffin. A few minutes afterwards, the symptoms commenced; they were those of suffocation, with a constant cough; there was no expectoration; the tongue, gums, and cheeks were blanched and swollen where the fluid touched them; recovery followed. A woman, aged 32, who had taken a quarter of a pint of paraffin, was found unconscious and very cold; the stomach-pump was used, and she recovered.[139] Hence it is tolerably certain, from the above instances, that should a case of petroleum poisoning occur, the expert will not have to deal with infinitesimal quantities; but while the odour of the oil will probably be distinctly perceptible, there will be also a sufficient amount obtained either from matters vomited, or the contents of the stomach, &c., so that no difficulty will be experienced in identifying it.

[136] Poisons, p. 656

[137] Brit. Med. Journ., Sept. 16, 1876, p. 365.

[138] Brit. Med. Journ., Oct. 14, 1876.

[139] Pharm. Journ., Feb. 12, 1875; also for other cases see Brit. Med. Journ., Nov. 4, 1876; and Köhler’s Physiol. Therap., p. 437.

§ 145. In order to separate petroleum from any liquid, the substances under examination must be carefully distilled in the manner recommended under “Ether.” The lighter petroleums will distil by the aid of a water-bath; but the heavier require a stronger heat; redistillation of the distillate may be necessary. The odour of the liquid, its inflammable character, and its other properties, will be sufficient for identification.

2. COAL-TAR-NAPHTHA--BENZENE.

§ 146. Coal-tar-naphtha in its crude state, is an extremely complex liquid, of a most disagreeable smell. Much benzene (C₆H₆) is present with higher homologues of the benzene series. Toluene (C₇H₈), naphthalene (C₁₀H₈), hydrocarbons of the paraffin series, especially hexane (C₆H₁₄), and hydrocarbons of the olefin series, especially pentylene, hexylene, and heptylene (C₅H₁₀, C₆H₁₂ and C₇H₁₄). Besides these, there are nitrogenised bases, such as aniline, picoline, and pyridine; phenols, especially carbolic acid; ammonia, ammonium sulphide, carbon disulphide, and probably other sulphur compounds; acetylene and aceto-nitrile. By distillation and fractional distillation are produced what are technically known ”once run” naphtha, 90 per cent. benzol, 50 and 90 per cent. benzol,[140] 30 per cent. benzol, solvent naphtha, and residue known as “last runnings.”

[140] Or 50/90 benzol, this indicates that 50 per cent. distils over below 100°; and 40, making in all 90, below 120°.

§ 147. Taylor[141] records a case in which a boy, aged 12, swallowed about 3 ozs. of naphtha, the kind usually sold for burning in lamps, and died with symptoms of narcotic poisoning. The child, after taking it, ran about in wild delirium, he then sank into a state of collapse, breathing stertorously, and the skin became cold and clammy. On vomiting being excited, he rejected about two tablespoonfuls of the naphtha, and recovered somewhat, but again fell into collapse with great muscular relaxation. The breathing was difficult; there were no convulsions; the eyes were fixed and glassy, the pupils contracted; there was frothing at the mouth. In spite of every effort to save him, he died in less than three hours after taking the poison. The body, examined three days after death, smelt strongly of naphtha, but the post-mortem appearances were in no way peculiar, save that the stomach contained a pint of semi-fluid matter, from which a fluid, having the characteristics of impure benzene, was separated.

[141] Op. cit., p. 657.

§ 148. The effects of the vapour of benzene have been studied by Eulenberg in experiments on cats and rabbits, and there are also available observations on men[142] who have been accidentally exposed to its influence. From these sources of information, it is evident that the vapour of benzene has a distinctly narcotic effect, while influencing also in a marked degree the spinal cord. There are, as symptoms, noises in the head, convulsive trembling and twitchings of the muscles, with difficulty of breathing.

[142] Dr. Stone, Med. Gaz., 1848, vol. xii. p. 1077.

DETECTION AND SEPARATION OF BENZENE.

§ 149. Benzene is separated from liquids by distillation, and may be recognised by its odour, and by the properties described at p. 130. The best process of identification, perhaps, is to purify and convert it into nitro-benzene, and then into aniline, in the following manner:--

1. =Purification.=--The liquid is agitated with a solution of caustic soda; this dissolves out of the benzene any bodies of an acid character, such as phenol, &c. The purified liquid should again be distilled, collecting that portion of the distillate which passes over between 65° and 100°; directly the thermometer attains nearly the 100°, the distillation should be stopped. The distillate, which contains all the benzene present, is next shaken with concentrated sulphuric acid in the cold; this will dissolve out all the hydrocarbons of the ethylene and acetylene series. On removing the layer of benzene from the acid, it must be again shaken up with dilute soda, so as to remove any trace of acid. The benzene is, by this rather complicated series of operations, obtained in a very fair state of purity, and may be converted into nitro-benzene, as follows:--

2. =Conversion into Nitro-Benzene.=--The oily liquid is placed in a flask, and treated with four times its volume of fuming nitric acid. The flask must be furnished with an upright condenser; a vigorous action mostly takes place without the application of heat, but if this does not occur, the flask may be warmed for a few minutes.

After the conversion is over, the liquid, while still warm, must be transferred into a burette furnished with a glass tap, or to a separating funnel, and all, except the top layer, run into cold water; if benzene was originally present, either oily drops of nitro-benzene will fall, or if the benzene was only in small quantity, a fine precipitate will gradually settle down to the bottom of the vessel, and a distinct bitter-almond smell be observed; but, if there be no benzene in the original liquid, and, consequently, no nitro-benzene formed, no such appearance will be observed.

3. =Conversion into Aniline.=--The nitro-benzene may itself be identified by collecting it on a wet filter, dissolving it off the filter by alcohol, acidifying the alcoholic solution by hydrochloric acid, and then boiling it for some time with metallic zinc. In this way aniline is formed by reduction. On neutralising and diluting the liquid, and cautiously adding a little clear solution of bleaching-powder, a blue or purple colour passing to brown is in a little time produced.

3. TERPENES--ESSENTIAL OILS--OIL OF TURPENTINE.

§ 150. The terpenes are hydrocarbons of the general formula C_{n}H_{2n-4}. The natural terpenes are divided into three classes:--

1. =The true terpenes=, formula (C₁₀H₁₆)--a large number of essential oils, such as those of turpentine, orange peel, nutmeg, caraway, anise, thyme, &c., are mainly composed of terpenes.

2. =The cedrenes=, formula (C₁₅H₂₄)--the essential oil of cloves, rosewood, cubebs, calamus, cascarilla, and patchouli belong to this class.

3. =The colophene hydrocarbons=, formula (C₂₀H₃₂), represented by colophony.

Of all these, oil of turpentine alone has any toxicological significance; it is, however, true that all the essential oils, if taken in considerable doses, are poisonous, and cause, for the most part, vascular excitement and complex nervous phenomena, but their action has not been very completely studied. They may all be separated by distillation, but a more convenient process for recovering an essential oil from a liquid is to shake it up with petroleum ether, separating the petroleum and evaporating spontaneously; by this means the oil is left in a fair state of purity.

4. OIL OF TURPENTINE--SPIRIT OF TURPENTINE--“TURPS.”

§ 151. Various species of pine yield a crude turpentine, holding in solution more or less resin. The turpentine may be obtained from this exudation by distillation, and when the first portion of the distillate is treated with alkali, and then redistilled, the final product is known under the name of “rectified oil of turpentine,” and is sometimes called “camphene.” It mainly consists of terebenthene. Terebenthene obtained from French turpentine differs in some respects from that obtained from English or American turpentine. They are both mobile, colourless liquids, having the well-known odour of turpentine and highly refractive; but the French terebenthene turns a ray of polarised light to the left -40·3° for the sodium ray, and the English to the right +21·5°; the latter terebenthene is known scientifically as austra-terebenthene. This action on polarised light is retained in the various compounds and polymers of the two turpentine oils.

The specific gravity of turpentine oil is ·864; its boiling point, when consisting of pure terebenthene, 156°, but impurities may raise it up to 160°; it is combustible and burns with a smoky flame. Oil of turpentine is very soluble in ether, petroleum ether, carbon disulphide, chloroform, benzene, fixed and essential oils, and by the use of these solvents it is conveniently separated from the contents of the stomach. It is insoluble in water, glycerin, and dilute alkaline and acid solutions; and very soluble in absolute alcohol, from which it may be precipitated by the addition of water.

It is polymerised by the action of strong sulphuric acid, the polymer, of course, boiling at a higher temperature than the original oil. With water it forms a crystalline hydrate (C₁₀H₂₀O₂,H₂O). On passing nitrosyl chloride gas into the oil, either pure or diluted with chloroform or alcohol, the mixture being cooled by ice, a white crystalline body is deposited, of the formula C₁₀H₁₆(NOCl). By treating this compound with alcoholic potash, the substitution product (C₁₀H₁₆NO) is obtained. By treating turpentine with an equal bulk of warm water, and shaking it in a large bottle with air, camphoric acid and peroxide of hydrogen are formed. When turpentine oil is left in contact with concentrated hydrochloric acid, there is formed terebenthene dihydrochloride (C₁₀H₁₆2HCl), which forms rhombic plates, insoluble in water, and decomposable by boiling alcoholic potash, with formation of terpinol, (C₁₀H₁₇)₂O. The dihydrochloride gives a colour-reaction with ferric chloride. This is an excellent test--not, it is true, confined to oil of turpentine--but common to the dihydrochlorides of all the terpenes. A few drops of the oil are stirred in a porcelain capsule with a drop of hydrochloric acid, and one of ferric chloride solution; on gently heating, there is produced first a rose colour, then a violet-red, and lastly a blue.

§ 152. =Effects of the Administration of Turpentine.=--L. W. Liersch[143] exposed animals to the vapour of turpentine, and found that a cat and a rabbit died within half an hour. There was observed uneasiness, reeling, want of power in the limbs (more especially in the hinder extremities), convulsions partial, or general, difficulty of respiration; and the heart’s action was quickened. Death took place, in part, from asphyxia, and in part was attributable to a direct action on the nervous centres. The autopsy showed congestion of the lungs, ecchymoses of the kidney, and much blood in the liver and spleen. Small doses of turpentine-vapour cause (according to Sir B. W. Richardson)[144] giddiness, deficient appetite, and anæmia. From half an ounce to an ounce is frequently prescribed in the country as a remedy for tape-worm; in smaller quantities it is found to be a useful medicine in a great variety of ailments. The larger doses produce a kind of intoxication with giddiness, followed often by purging and strangury, not unfrequently blood and albumen (or both) is found in the urine. When in medical practice I have given the oil, and seen it given by others, in large doses for tape-worm to adults, in perhaps 40 cases, but in no one instance were the symptoms severe; the slight intoxication subsided quickly, and in a few hours the patients recovered completely. Nevertheless it has been known to destroy the lives of children, and cause most serious symptoms in adults. Two fatal cases are mentioned by Taylor; one was that of a child who died fifteen hours after taking half an ounce of the oil; in another an infant, five months old, died rapidly from a teaspoonful. The symptoms in these fatal cases were profound coma and slight convulsions; the pupils were contracted, and there was slow and irregular breathing. Turpentine is eliminated in a changed form by the kidneys, and imparts an odour of violet to the urine; but the nature of the odoriferous principle has not yet been investigated.

[143] Clarus in Schmidt’s Jahrbücher, Bd. cxvii., i. 1863; and Vierteljahrsschr. für ger. Med., xxii., Oct. 1862.

[144] Brit. and For. Med.-Chir. Review, April 1863.

II.--Camphor.

§ 153. A great many essential oils deposit, after exposure to air, camphors produced by oxidation of their terpenes. Ordinary camphor is imported in the rough state from China and Japan, and is prepared by distilling with water the wood of Camphora officinarum; it is resublimed in England. The formula of camphor is C₁₀H₁₆O; it has a density of ·986 to ·996; melts at 175°, and boils at 205°. It is readily sublimed, especially in a vacuum, and is indeed so volatile at all temperatures, that a lump of camphor exposed to the air wastes away. It is somewhat insoluble in water (about 1 part in 1000), but this is enough to impart a distinct taste to the water; it is insoluble in chloroform, ether, acetone, acetic acid, carbon disulphide, and oils. It has a fragrant odour and a burning taste. A 10 per cent. solution in alcohol turns a ray of polarised light to the right +42·8°. By distillation with zinc chloride, cymene and other products are produced. By prolonged treatment with nitric acid, camphor is oxidised to camphoric acid (C₁₀H₁₆O₄). Camphor unites with bromine to form a crystalline, unstable dibromide, which splits up on distillation into hydrobromic acid and monobrom-camphor (C₁₀H₁₅BrO). The latter is used in medicine; it crystallises in prisms fusible at 76°, and is readily soluble in alcohol.

§ 154. =Pharmaceutical Preparations.=--The preparations officinal in the British Pharmacopœia are camphor water--water saturated with camphor, containing about one part per thousand.

=Camphor Liniment.=--A solution of camphor in olive oil, strength 25 per cent.

=Compound Camphor Liniment.=--Composed of camphor, oil of lavender, strong solution of ammonia and alcohol; strength in camphor about 11 per cent.

=Spirit of Camphor.=--A solution of camphor in spirit; strength, 10 per cent.

Camphor is also a constituent of the compound tincture of camphor; but in this case it may be considered only a flavouring agent. There is a homœopathic solution of camphor in spirit (Rubini’s Essence of Camphor). The solution is made by saturating alcohol with camphor; it is, therefore, very strong--about half the bulk consisting of camphor. Camphor is used in veterinary medicine, both externally and internally.

§ 155. =Symptoms.=--Camphor acts energetically on the brain and nervous system, especially if it is given in strong alcoholic solution, and thus placed under conditions favouring absorption. Some years ago, Dr. G. Johnson[145] published a series of cases arising from the injudicious use of “homœopathic solution of camphor,” from 7 to 40 drops of Rubini’s homœopathic camphor taken for colds, sore throat, &c., having produced coma, foaming at the mouth, convulsions, and partial paralysis. All the patients recovered, but their condition was for a little time alarming.

[145] Brit. Med. Journ., Feb. 27, 1878, p. 272; see also ibid., Feb. 1875.

The cases of fatal poisoning by camphor are very rare. A woman, aged 46, pregnant four months, took 12 grms. (about 184 grains) in a glass of brandy for the purpose of procuring abortion. In a very short time the symptoms commenced; she had intolerable headache, the face was flushed, and there was a sensation of burning in the stomach. In eight hours after taking the dose, she had strangury and vomiting, and the pain in the epigastrium was intense. These symptoms continued with more or less severity until the third day, when she became much worse. Her face was pale and livid, the eyes hollow, the skin cold and insensible, pulse weak and thready, breathing laboured. There were violent cramps in the stomach and retention of urine for twenty-four hours, and then coma. The patient lingered on yet another three days, aborted, and died.[146]

[146] Journ. de Chim. Méd., May 1860.

Dr. Schaaf[147] has recorded three cases of poisoning--one of which was fatal. A woman gave about half a teaspoonful of a camphor solution to each of her three children, the ages being respectively five and three years and fifteen months. The symptoms noted were pallor of the face, a burning pain in the throat, thirst, vomiting, purging, convulsions, and afterwards coma. The youngest child died in seven hours; the others recovered. The smallest dose known to have produced violent symptoms in an adult is 1·3 grm. (20 grains); the largest dose known to have been recovered from is 10·4 grms. (160 grains).[148]

[147] Journ. de Chim. Méd., 1850, p. 507.

[148] Taylor on Poisons, 3rd ed., 661.

§ 156. =Post-mortem Appearances.=--The bodies of animals or persons dying from poisoning by camphor, smell strongly of the substance. The mucous membrane of the stomach has been found inflamed, but there seem to be no characteristic lesions.

§ 157. =Separation of Camphor from the Contents of the Stomach.=--The identification of camphor would probably in no case present any difficulty. It may be readily dissolved out from organic fluids by chloroform. If dissolved in fixed oils, enough for the purposes of identification may be obtained by simple distillation. It is precipitated from its alcoholic solution by the addition of water.

III.--Alcohols.

1. ETHYLIC ALCOHOL.

§ 158. The chemical properties of ordinary alcohol are fully described, with the appropriate tests, in “Foods,” pp. 369-384, and the reader is also referred to the same volume for the composition and strength of the various alcoholic drinks.

=Statistics.=--If we were to include in one list the deaths indirectly due to chronic, as well as acute poisoning by alcohol, it would stand first of all poisons in order of frequency, but the taking of doses so large as to cause death in a few hours is rare. The deaths from alcohol are included by the English registrar-general under two heads, viz., those returned as dying from delirium tremens, and those certified as due directly to intemperance.

During the twenty-five years, from 1868 to 1892, 30,219 deaths have been registered as due to intemperance, which gives an average of 1209 per year. The rate per million has varied during the period from 29 to 71; and the figures taken as a whole show that deaths from intemperance appear to be increasing; the increase may be only apparent, not real, for it is a significant circumstance that deaths registered under liver diseases show a corresponding decrease; it is, therefore, not unlikely that deaths which formerly would be ascribed to liver disease, are more often now stated to be the effects of intemperance.

Deaths directly due to large doses of alcohol are not uncommon; during the ten years ending 1892, 105 deaths (81 males and 24 females) were ascribed under the head of “accident or negligence” directly to alcohol.

§ 159. =Criminal or Accidental Alcoholic Poisoning.=--Suicide by alcohol, in the common acceptation of the term, is rare, and murder still rarer, though not unknown. In the ten years ending 1892, only three deaths from alcohol (1 male and 2 females) are recorded as suicidal. Perhaps the most common cause of fatal acute poisoning by alcohol is either a foolish wager, by which a man bets that he can drink so many glasses of spirits without bad effect; or else the drugging of a person already drunk by his companions in a sportive spirit.

§ 160. =Fatal Dose.=--It is difficult to say what would be likely to prove a lethal dose of alcohol, for a great deal depends, without doubt, on the dilution of the spirit, since the mere local action of strong alcohol on the mucous membranes of the stomach, &c., is severe (one may almost say corrosive), and would aid the more remote effects. In Maschka’s case,[149] a boy of nine years and a girl of five, died from about two and a half ounces of spirit of 67 per cent. strength, or 48·2 c.c. (1·7 oz.) of absolute alcohol.

[149] Recorded by Maschka (Gutachten der Prager Facultät, iv. 239; see also Maschka’s Handbuch der gericht. Medicin, Band. ii. p. 384). The following is a brief summary:--Franz. Z., nine years old, and Caroline Z., eight years old, were poisoned by their stepfather with spirit of 67 per cent. strength taken in small quantities by each--at first by persuasion, and the remainder administered by force. About one-eighth of a pint is said to have been given to each child. Both vomited somewhat, then lying down, stertorous breathing at once came on, and they quickly died. The autopsy, three days after death, showed dilatation of the pupils; rigor mortis present in the boy, not in the girl; and the membranes of the brain filled with dark fluid blood. The smell of alcohol was perceptible on opening the chest; the mucous membrane of the bronchial tubes and gullet was normal, both lungs œdematous, the fine tubes gorged with a bloody frothy fluid, and the mucous membrane of the whole intestinal canal was reddened. The stomach was not, unfortunately, examined, being reserved for chemical analysis. The heart was healthy; the pericardium contained some straw-coloured fluid. Chemical analysis gave an entirely negative result, which must have been from insufficient material having been submitted to the analyst, for I cannot see how the vapours of alcohol could have been detected by the smell, and yet have evaded chemical processes.

In a case related by Taylor, a child, seven years old, died from some quantity of brandy, probably about 113·4 c.c. (4 ozs.), which would be equal to at least 56·7 c.c. (2 ozs.) of absolute alcohol. From other cases in which the quantity of absolute alcohol can be, with some approximation to the truth, valued, it is evident that, for any child below ten or twelve, quantities of from 28·3 to 56·6 c.c. (1-2 ozs.) of absolute alcohol contained in brandy, gin, &c., would be a highly dangerous and probably fatal dose; while the toxic dose for adults is somewhere between 71·8-141·7 c.c. (2·5-5 ozs.).

§ 161. =Symptoms.=--In the cases of rapid poisoning by a large dose of alcohol, which alone concern us, the preliminary, and too familiar excitement of the drunkard, may be hardly observable; but the second stage, that of depression, rapidly sets in; the unhappy victim sinks down to the ground helpless, the face pale, the eyes injected and staring, the pupils dilated, acting sluggishly to light, and the skin remarkably cold. Fräntzel[150] found, in a case in which the patient survived, a temperature of only 24·6° in the rectum, and in that of another person who died, a temperature of 23·8°. The mucous membranes are of a peculiar dusky blue; the pulse, which at first is quick, soon becomes slow and small; the respiration is also slowed, intermittent, and stertorous; there is complete loss of consciousness and motion; the breath smells strongly of the alcoholic drink, and if the coma continues there may be vomiting and involuntary passing of excreta. Death ultimately occurs through paralysis of the respiratory centres. Convulsions in adults are rare, in children frequent. Death has more than once been immediately caused, not by the poison, but by accidents dependent upon loss of consciousness. Thus food has been sucked into the air-tubes, or the person has fallen, so that the face was buried in water, ordure, or mud; here suffocation has been induced by mechanical causes.

[150] Temperaturerniedrigung durch Alcoholintoxication, Charité Annalen, i. 371.

A remarkable course not known with any other narcotic is that in which the symptoms remit, the person wakes up, as it were, moves about and does one or more rational acts, and then suddenly dies. In this case also, the death is not directly due to alcohol, but indirectly--the alcohol having developed œdema, pneumonia, or other affection of the lungs, which causes the sudden termination when the first effect of the poison has gone off. The time that may elapse from the commencement of coma till death varies from a few minutes to days; death has occurred after a quarter of an hour, half an hour, and an hour. It has also been prolonged to three, four, and six days, during the whole of which the coma has continued. The average period may, however, be put at from six to ten hours.

§ 162. =Post-mortem Appearances.=--Cadaveric rigidity lasts tolerably long. Casper has seen it still existing nine days after death, and Seidel[151] seven days (in February). Putrefaction is retarded in those cases in which a very large dose has been taken, but this is not a very noticeable or constant characteristic. The pupils are mostly dilated. The smell of alcohol should be watched for; sometimes it is only present in cases where but a short time has elapsed between the taking of the poison and death; putrefaction may also conceal it, but under favourable circumstances, especially if the weather is cold, the alcoholic smell may remain a long time. Alcohol may cause the most intense redness and congestion of the stomach. The most inflamed stomach I ever saw, short of inflammation by the corrosive poisons, was that of a sailor, who died suddenly after a twenty-four hours’ drinking bout: all the organs of the body were fairly healthy, the man had suffered from no disease; analysis could detect no poison but alcohol; and the history of the case, moreover, proved clearly that it was a pure case of alcoholic poisoning.

[151] Seidel, Maschka’s Handbuch, Bd. ii. p. 380.

In a case related by Taylor, in which a child drank 4 ozs. of brandy and died, the mucous membrane of the stomach presented patches of intense redness, and in several places was thickened and softened, some portions being actually detached and hanging loose, and there were evident signs of extravasations of blood. The effect may not be confined to the stomach, but extend to the duodenum and even to the whole intestinal canal. The blood is generally dark and fluid, and usually the contents of the skull are markedly hyperæmic, the pia very full of blood, the sinuses and plexus gorged; occasionally, the brain-substance shows signs of unusual congestion; serum is often found in the ventricles. The great veins of the neck, the lungs, and the right side of the heart, are very often found full of blood, and the left side empty. Œdema of the lungs also occurs with tolerable frequency. The great veins of the abdomen are also filled with blood, and if the coma has been prolonged, the bladder will be distended with urine. A rare phenomenon has also been noticed--namely, the occurrence of blebs on the extremities, &c., just as if the part affected had been burnt or scalded. Lastly, with the changes directly due to the fatal dose may be included all those degenerations met with in the chronic drinker, provided the case had a history of previous intemperance.

§ 163. =Excretion of Alcohol.=--Alcohol, in the diluted form, is quickly absorbed by the blood-vessels of the stomach, &c., and circulates in the blood; but what becomes of it afterwards is by no means settled. I think there can be little doubt that the lungs are the main channels through which it is eliminated; with persons given up to habits of intemperance, the breath has constantly a very peculiar ethereal odour, probably dependent upon some highly volatile oxidised product of alcohol.

Alcohol is eliminated in small proportion only by the kidneys. Thudichum, in an experiment[152] by which 4000 grms. of absolute alcohol were consumed by thirty-three men, could only find in the collected urine 10 grms. of alcohol. The numerous experiments by Dupré also establish the same truth, that but a fraction of the total alcohol absorbed is excreted by the kidneys. According to Lallemand, Perrin, and Duroy the content of the brain in alcohol is more than that of the other organs. I have found also that the brain after death has a wonderful attraction for alcohol, and yields it up at a water-heat very slowly and with difficulty. In one experiment, in which a finely-divided portion of brain, which had been soaking in alcohol for many weeks, was submitted to a steam heat of 100°, twenty-four hours’ consecutive heating failed to expel every trace of spirit.

[152] See Thudichum’s Pathology of the Urine, London, 1877, in which both his own and Dr. Dupré’s experiments are summarised.

It is probable that true alcoholates of the chemical constituents of the brain are formed. In the case of vegetable colloidal bodies, such, for example, as the pulp of cherries, a similar attraction has been observed, the fruit condensing, as it were, the alcohol in its own tissues, and the outer liquid being of less alcoholic strength than that which can be expressed from the steeped cherries. Alcohol is also excreted by the sweat, and minute fractions have been found in the fæces.

§ 164. =Toxicological Detection of Alcohol= (see “Foods,” pp. 406-419).--The living cells of the body produce minute quantities of alcohol, as also some of the bacteria normally inhabiting the small intestine produce small quantities of alcohol, and it is often found in traces in putrefying fluids. Hence, mere qualitative proofs of the presence of alcohol are insufficient on which to base an opinion as to whether alcohol had been taken during life or not, and it will be necessary to estimate the quantity accurately by some of the processes detailed in “Foods,” p. 409, et seq. In those cases in which alcohol is found in quantity in the stomach, there can, of course, be no difficulty; in others, the whole of the alcohol may have been absorbed, and chemical evidence, unless extremely definite, must be supplemented by other facts.

2. AMYLIC ALCOHOL.

§ 165. =Amylic Alcohol=--Formula, C₅H₁₁HO.--There is more than one amylic alcohol according to theory; eight isomers are possible, and seven are known. The amylic alcohols are identical in their chemical composition, but differ in certain physical properties, primary amylic alcohol boiling at 137°, and iso-amyl alcohol at 131·6°. The latter has a specific gravity of ·8148, and is the variety produced by fermentation and present in fusel oil.

§ 166. The experiments of Eulenberg[153] on rabbits, Cross[154] on pigeons, Rabuteau[155] on frogs, and Furst on rabbits, with those of Sir B. W. Richardson[156] on various animals, have shown it to be a powerful poison, more especially if breathed in a state of vapour.

[153] Gewerbe Hygiene, 1876, p. 440.

[154] De l’Alcohol Amylique et Méthyl sur l’Organisme (Thèse), Strasburg, 1863.

[155] “Ueber die Wirkung des Aethyl, Butyl u. Amyl Alcohols,” L’Union, Nos. 90, 91, 1870. Schmidt’s Jahrb., Bd. 149, p. 263.

[156] Trans. Brit. Association, 1864, 1865, and 1866. Also, Brit. and Foreign Med. Chir. Rev., Jan. 7, 1867, p. 247.

Richardson, as the result of his investigations, considers that amyl alcohol when breathed sets up quite a peculiar class of symptoms which last for many hours, and are of such a character, that it might be thought impossible for the animal to recover, although they have not been known to prove fatal. There is muscular paralysis with paroxysms of tremulous convulsions; the spasms are excited by touching the animal, breathing upon it, or otherwise subjecting it to trifling excitation.

§ 167. Hitherto, neither the impure fusel oil, nor the purer chemical preparation, has had any toxicological importance. Should it be necessary at any time to recover small quantities from organic liquids, the easiest way is to shake the liquid up with chloroform, which readily dissolves amylic alcohol, and on evaporation leaves it in a state pure enough to be identified. Amyl alcohol is identified by the following tests:--(1) Its physical properties; (2) if warmed with twice its volume of strong sulphuric acid, a rose or red colour is produced; (3) heated with an acetate and strong sulphuric acid, amyl acetate, which has the odour of the jargonelle pear, is formed; (4) heated with sulphuric acid and potassic dichromate, valeric aldehyde is first produced, and then valeric acid is formed; the latter has a most peculiar and strong odour.

§ 168. =Amyl Nitrite, Iso-amyl Ester Nitrite= (C₅H₁₁NO₂).--Boiling point 97° to 99°, specific gravity ·877. Amyl nitrite is a limpid, and, generally, slightly yellow liquid; it has a peculiar and characteristic odour. On heating with alcoholic potash, the products are nitrite of potash and amylic alcohol; the amylic alcohol may be distilled off and identified. The presence of a nitrite in the alkaline solution is readily shown by the colour produced, by adding a few drops of a solution of meta-phenylenediamine.

Sir B. W. Richardson and others have investigated the action of amyl nitrite, as well as that of the acetate and iodide; they all act in a similar manner, the nitrite being most potent. After absorption, the effects of amyl nitrite are especially seen on the heart and circulation: the heart acts violently, there is first dilatation of the capillaries, then this is followed by diminished action of the heart and contraction of the capillaries.

According to Richardson, it suspends the animation of frogs. No other substance known will thus suspend a frog’s animation for so long a time without killing it. Under favourable circumstances, the animal will remain apparently dead for many days, and yet recover. Warm-blooded animals may be thrown by amyl nitrite into a cataleptic condition. It is not an anæsthetic, and by its use consciousness is not destroyed, unless a condition approaching death be first produced. When this occurs there is rarely recovery, the animal passes into actual death.

=Post-Mortem Appearances.=--If administered quickly, the lungs and all the other organs are found blanched and free from blood, the right side of the heart gorged with blood, the left empty, the brain being free from congestion. If administered slowly, the brain is found congested, and there is blood both on the left and right sides of the heart.

IV.--Ether.

§ 169. =Ether, Ethylic Ether, Ethyl Oxide,= (C₂H₅)₂O.--Ethylic ether is a highly mobile liquid of peculiar penetrating odour and sweetish pungent taste. It is perfectly colourless, and evaporates so rapidly, that when applied in the form of spray to the skin, the latter becomes frozen, and is thus deprived of sensibility.

Pure ether has a density of ·713, its boiling-point is 35°, but commercial samples, which often contain water (1 part of water is soluble in 35 of ether), may have a higher gravity, and also a higher boiling-point. The readiest way to know whether an ether is anhydrous or not, is to shake it up with a little carbon disulphide. If it is hydrous, the mixture is milky. Methylated ether is largely used in commerce; its disagreeable odour is due to contamination by methylated compounds; otherwise the ether made from methylated spirit is ethylic ether, for methylic ether is a gas which escapes during the process. Hence the term “methylated” ether is misleading, for it contains no methylic ether, but is essentially a somewhat impure ethylic ether.

§ 170. =Ether as a Poison.=--Ether has but little toxicological importance. There are a few cases of death from its use as an anæsthetic, and a few cases of suicide. Ether is used by some people as a stimulant, but ether drinkers are uncommon. It causes an intoxication very similar to that of alcohol, but of brief duration. In a case of chronic ether-taking recorded by Martin,[157] in which a woman took daily doses of ether for the purpose of allaying a gastric trouble, the patient suffered from shivering or trembling of the hands and feet, muscular weakness, cramp in the calves of the legs, pain in the breast and back, intermittent headaches, palpitation, singing in the ears, vomitings, and wakefulness; the ether being discontinued, the patient recovered. In one of Orfila’s experiments, half an ounce of ether was administered to a dog. The animal died insensible in three hours. The mucous membrane of the stomach was found highly inflamed, the inflammation extending somewhat into the duodenum; the rest of the canal was healthy. The lungs were gorged with fluid blood.

[157] Virchow’s Jahresber., 1870.

§ 171. =Fatal Dose.=--The fatal dose of ether, when taken as a liquid, is not known. 4 grms. (1·28 drms.) cause toxic symptoms, but the effect soon passes. Buchanan has seen a brandy-drinker consume 25 grms. (7 drms.) and yet survive. It is probable that most adults would be killed by a fluid ounce (28·4 c.c.).

§ 172. =Ether as an Anæsthetic.=--Ether is now much used as an anæsthetic, and generally in conjunction with chloroform. Anæsthesia by ether is said to compare favourably with that produced by chloroform. In 92,000 cases of operations performed under ether, the proportion dying from the effects of the anæsthetic was only ·3 per 10,000 (Morgan), while chloroform gives a higher number (see p. 149). The mortality in America, again, from a mixture of chloroform and ether in 11,000 cases is reckoned at 1·7 per 10,000; but this proportion is rather above some of the calculations relative to the mortality from pure chloroform, so that the question can hardly be considered settled. The symptoms of ether narcosis are very similar to those produced by chloroform. The chief point of difference appears to be its action on the heart. Ether, when first breathed, stimulates the heart’s action, and the after-depression that follows never reaches so high a grade as with chloroform. Ether is said to kill by paralysing the respiration, and in cases which end fatally the breathing is seen to stop suddenly: convulsions have not been noticed. The post-mortem appearances, as in the case of chloroform, are not characteristic.

§ 173. =Separation of Ether from Organic Fluids, &c.=--Despite the low boiling-point of ether, it is by no means easy to separate it from organic substances so as to recover the whole of the ether present. The best way is to place the matters in a flask connected with an ordinary Liebig’s condenser, the tube of the latter at its farther end fitting closely into the doubly perforated cork of a flask. Into the second perforation is adapted an upright tube about 2 feet long, which may be of small diameter, and must be surrounded by a freezing mixture of ice and salt. The upper end of this tube is closed by a thistle-head funnel with syphon, and in the bend of the syphon a little mercury serves as a valve. Heat is now applied to the flask by means of a water-bath, and continued for several hours; the liquid which has distilled over is then treated with dry calcic chloride and redistilled exactly in the same way. To this distillate again a similar process may be used, substituting dry potassic carbonate for the calcic chloride. It is only by operating on these principles that the expert can recover in an approximate state of anhydrous purity such a volatile liquid. Having thus obtained it pure, it may be identified (1) by its smell, (2) by its boiling-point, (3) by its inflammability, and (4) by its reducing chromic acid. The latter test may be applied to the vapour. An asbestos fibre is soaked in a mixture of strong sulphuric acid and potassic dichromate, and then placed in the tube connected with the flask--the ethereal (or alcoholic) vapour passing over the fibre, immediately reduces the chromic acid to chromic oxide, with the production of a green colour.

V.--Chloroform.

CHLOROFORM, TRICHLOROMETHANE OR METHENYL CHLORIDE (CHCl₃).

§ 174. Chloroform appears to have been discovered independently by Soubeiran and Liebig, about 1830. It was first employed in medicine by Simpson, of Edinburgh, as an anæsthetic. Pure chloroform has a density of 1·491 at 17°, and boils at 60·8°; but commercial samples have gravities of from 1·47 to 1·491. It is a colourless liquid, strongly refracting light; it cannot be ignited by itself, but, when mixed with alcohol, burns with a smoky flame edged with green. Its odour is heavy, but rather pleasant; the taste is sweet and burning.

Chloroform sinks in water, and is only slightly soluble in that fluid (·44 in 100 c.c.), it is perfectly neutral in reaction, and very volatile. When rubbed on the skin, it should completely evaporate, leaving no odour. Pure absolute chloroform gives an opaline mixture if mixed with from 1 to 5 volumes of alcohol, but with any quantity above 5 volumes the mixture is clear; it mixes in all proportions with ether. Chloroform coagulates albumen, and is an excellent solvent for most organic bases--camphor, caoutchouc, amber, opal, and all common resins. It dissolves phosphorus and sulphur slightly--more freely iodine and bromine. It floats on hydric sulphate, which only attacks it at a boiling heat.

Chloroform is frequently impure from faulty manufacture or decomposition. The impurities to be sought are alcohol, methylated chloroform,[158] dichloride of ethylene (C₂H₄Cl₂), chloride of ethyl (C₂H₅Cl), aldehyde, chlorine, hydrochloric, hypochlorous, and traces of sulphuric acid: there have also been found chlorinated oils. One of the best tests for contamination by alcohol, wood spirit, or ether, is that known as Roussin’s; dinitrosulphide of iron[159] is added to chloroform. If it contain any of these impurities, it acquires a dark colour, but if pure, remains bright and colourless.

[158] Methylated chloroform is that which is prepared from methylated spirit. It is liable to more impurities than that made from pure alcohol, but, of course, its composition is the same, and it has recently been manufactured from this source almost chemically pure.

[159] Made by slowly adding ferric sulphate to a boiling solution of ammonic sulphide and potassic nitrite, as long as the precipitate continues to redissolve, and then filtering the solution.

The presence of alcohol or ether, or both, may also be discovered by the bichromate test, which is best applied as follows:--A few milligrammes of potassic bichromate are placed at the bottom of a test-tube with four or five drops of sulphuric acid, which liberates the chromic acid; next, a very little water is added to dissolve the chromic acid; and lastly, the chloroform. The whole is now shaken, and allowed to separate. If the chloroform is pure, the mass is hardly tinged a greenish-yellow, and no layer separates. If, however, there is anything like 5 per cent. of alcohol or ether present, the deep green of chromium chloride appears, and there is a distinct layer at the bottom of the tube.

Another way to detect alcohol in chloroform, and also to make an approximate estimation of its quantity, is to place 20 c.c. of chloroform in a burette, and then add 80 c.c. of water. On shaking violently, pure chloroform will sink to the bottom in clear globules, and the measurement will be as nearly as possible the original quantity; but if anything like a percentage of alcohol be present, the chloroform is seen to be diminished in quantity, and its surface is opalescent, the diminution being caused by the water dissolving out the alcohol. The addition of a few drops of potash solution destroys the meniscus, and allows of a close reading of the volume. The supernatant water may be utilised for the detection of other impurities, and tested for sulphuric acid by baric chloride, for free chlorine and hypochlorous acid by starch and potassic iodide, and for hydrochloric acid by silver nitrate.[160] Fuchsine, proposed by Stœdeler, is also a delicate reagent for the presence of alcohol in chloroform, the sample becoming red in the presence of alcohol, and the tint being proportionate to the quantity present. The most delicate test for alcohol is, however, the iodoform test fully described in “Foods,” p. 375.[161] Dichloride of ethylene is detected by shaking up the chloroform with dry potassic carbonate, and then adding metallic potassium. This does not act on pure chloroform, but only in presence of ethylene dichloride, when the gaseous chlor-ethylene (C₂H₃Cl) is evolved. Ethyl-chloride is detected by distilling the chloroform and collecting the first portions of the distillate; it will have a distinct odour of ethyl-chloride should it be present. Methyl compounds and empyreumatic oils are roughly detected by allowing the chloroform to evaporate on a cloth. If present, the cloth, when the chloroform has evaporated, will have a peculiar disagreeable odour. Aldehyde is recognised by its reducing action on argentic nitrate; the mineral acids by the reddening of litmus paper, and the appropriate tests. Hypochlorous acid first reddens, and then bleaches, litmus-paper.

[160] Neither an alcoholic nor an aqueous solution of silver nitrate causes the slightest change in pure chloroform.

[161] An attempt has been made by Besnou to estimate the amount of alcohol by the specific gravity. He found that a chloroform of 1·4945 gravity, mixed with 5 per cent. of alcohol, gave a specific gravity of 1·4772; 10 per cent., 1·4602; 20 per cent., 1·4262; and 25 per cent., 1·4090. It would, therefore, seem that every percentage of alcohol lowers the gravity by ·0034.

Dr. Dott, Pharm. Journ., 1894, p. 629, gives the following tests:--Specific gravity, 1·490 to 1·495. On allowing ½ fluid drm. to evaporate from a clean surface, no foreign odour is perceptible at any stage of the evaporation. When 1 fluid drm. is agitated with an equal volume of solution of silver nitrate, no precipitate or turbidity is produced after standing for five minutes. On shaking up the chloroform with half its volume of distilled water, the water should not redden litmus-paper. When shaken with an equal volume of sulphuric acid, little or no colour should be imparted to the acid.

§ 175. The ordinary method of manufacturing chloroform is by distilling alcohol with chlorinated lime; but another mode is now much in use--viz., the decomposition of chloral hydrate. By distilling it with a weak alkali, this process yields such a pure chloroform, that, for medicinal purposes, it should supersede every other.

Poisonous Effects of Chloroform.

1. AS A LIQUID.

§ 176. =Statistics.=--Falck finds recorded in medical literature 27 cases of poisoning by chloroform having been swallowed--of these 15 were men, 9 were women, and 3 children. Eighteen of the cases were suicidal, and 10 of the 18 died; the remainder took the liquid by mistake.

§ 177. =Local Action of Chloroform.=--When applied to the skin or mucous membranes in such a way that the fluid cannot evaporate--as, for example, by means of a cloth steeped in chloroform laid on the bare skin, and covered over with some impervious material--there is a burning sensation, which soon ceases, and leaves the part anæsthetised, while the skin, at the same time, is reddened and sometimes even blistered.

§ 178. Chloroform added to blood, or passed through it in the state of vapour, causes it to assume a peculiar brownish colour owing to destruction of the red corpuscles and solution of the hæmoglobin in the plasma. The change does not require the presence of atmospheric air, but takes place equally in an atmosphere of hydrogen. It has been shown by Schmiedeberg that the chloroform enters in some way into a state of combination with the blood-corpuscles, for the entire quantity cannot be recovered by distillation; whereas the plasma, similarly treated, yields the entire quantity which has in the first place been added. Schmiedeberg also asserts that the oxygen is in firmer combination with the chloroformised blood than usual, as shown by its slow extraction by stannous oxide. Muscle, exposed to chloroform liquid by arterial injection, quickly loses excitability and becomes rigid. Nerves are first stimulated, and then their function for the time is annihilated; but on evaporation of the chloroform, the function is restored.

§ 179. =General Effects of the Liquid.=--However poisonous in a state of vapour, chloroform cannot be considered an extremely active poison when taken into the stomach as a liquid, for enormous quantities, relatively, have been drunk without fatal effect. Thus, there is the case recorded by Taylor, in which a man, who had swallowed 113·4 grms. (4 ozs.), walked a considerable distance after taking the dose. He subsequently fell into a state of coma, with dilated pupils, stertorous breathing, and imperceptible pulse. These symptoms were followed by convulsions, but the patient recovered in five days.

In a case related by Burkart,[162] a woman desired to kill herself with chloroform, and procured for that purpose 50 grms. (a little less than one ounce and a half); she drank some of it, but the burning taste and the sense of heat in the mouth, throat, and stomach, prevented her from taking the whole at once. After a few moments, the pain passing off, she essayed to drink the remainder, and did swallow the greater portion of it, but was again prevented by the suffering it caused. Finally, she poured what remained on a cloth, and placing it over her face, soon sank into a deep narcosis. She was found lying on the bed very pale, with blue lips, and foaming a little at the mouth; the head was rigidly bent backwards, the extremities were lax, the eyes were turned upwards and inwards, the pupils dilated and inactive, the face and extremities were cold, the body somewhat warmer, there was no pulse at the wrist, the carotids beat feebly, the breathing was deep and rattling, and after five or six inspirations ceased. By the aid of artificial respiration, &c., she recovered in an hour.

[162] Vierteljahrsschr. für ger. Med., 1876.

A still larger dose has been recovered from in the case of a young man, aged 23,[163] who had swallowed no less than 75 grms. (2·6 ozs.) of chloroform, but yet, in a few hours, awoke from the stupor. He complained of a burning pain in the stomach; on the following day he suffered from vomiting, and on the third day symptoms of jaundice appeared,--a feature which has been several times noticed as an effect of chloroform.

[163] Brit. Med. Journ., 1879.

On the other hand, even small doses have been known to destroy life. In a case related by Taylor, a boy, aged 4, swallowed 3·8 grms. (1 drm.) of chloroform and died in three hours, notwithstanding that every effort was used for his recovery.

§ 180. The smallest dose that has proved fatal to an adult is 15 grms. (a little over 4 drms.).

From twenty-two cases in which the quantity taken had been ascertained with some degree of accuracy, Falck draws the following conclusions:--In eight of the cases the dose was between 4 and 30 grms., and one death resulted from 15 grms. As for the other fourteen persons, the doses varied from 35 to 380 grms., and eight of these patients died--two after 40, two after 45, one after 60, 90, 120, and 180 grms. respectively. Hence, under conditions favouring the action of the poison, 15 grms. (4·3 drms.) may be fatal to an adult, while doses of 40 grms. (11·3 drms.) and upwards will almost certainly kill.

§ 181. =Symptoms.=--The symptoms can be well gathered from the cases quoted. They commence shortly after the taking of the poison; and, indeed, the local action of the liquid immediately causes first a burning sensation, followed by numbness.

Often after a few minutes, precisely as when the vapour is administered, a peculiar, excited condition supervenes, accompanied, it may be, by delirium. The next stage is narcosis, and the patient lies with pale face and livid lips, &c., as described at p. 147; the end of the scene is often preceded by convulsions. Sometimes, however, consciousness returns, and the irritation of the mucous membranes of the gastro-intestinal canal is shown by bloody vomiting and bloody stools, with considerable pain and general suffering. In this way, a person may linger several days after the ingestion of the poison. In a case observed by Pomeroy, the fatal malady was prolonged for eight days. Among those who recover, a common sequela, as before mentioned, is jaundice.

A third form of symptoms has been occasionally observed, viz.:--The person awakes from the coma, the breathing and pulse become again natural, and all danger seems to have passed, when suddenly, after a longer or shorter time, without warning, a state of general depression and collapse supervenes, and death occurs.

§ 182. =Post-mortem Appearances.=--The post-mortem appearances from a fatal dose of liquid chloroform mainly resolve themselves into redness of the mucous membrane of the stomach, though occasionally, as in Pomeroy’s case, there may be an ulceration. In a case recorded by Hoffman,[164] a woman, aged 30, drank 35 to 40 grms. of chloroform and died within the hour. Almost the whole of the chloroform taken was found in the stomach, as a heavy fluid, coloured green, through the bile. The epithelium of the pharynx, epiglottis, and gullet was of a dirty colour, partly detached, whitened, softened, and easily stripped off. The mucous membrane of the stomach was much altered in colour and consistence, and, with the duodenum, was covered with a tenacious grey slime. There was no ecchymosis.

[164] Lehrbuch der ger. Medicin, 2te Aufl.

2. THE VAPOUR OF CHLOROFORM.

§ 183. =Statistics.=--Accidents occur far more frequently in the use of chloroform vapour for anæsthetic purposes than in the use of the liquid.

Most of the cases of death through chloroform vapour, are those caused accidentally in surgical and medical practice. A smaller number are suicidal, while for criminal purposes, its use is extremely infrequent.

The percentage of deaths caused by chloroform administered during operations is unaccountably different in different years, times, and places. The diversity of opinion on the subject is partly (though not entirely) explicable, by the degrees of purity in the anæsthetic administered, the different modes of administration, the varying lengths of time of the anæsthesia, and the varying severity of the operations.

During the Crimean War, according to Baudens and Quesnoy, 30,000 operations were done under chloroform, but only one death occurred attributable to the anæsthetic. Sansom[165] puts the average mortality at ·75 per 10,000, Nussbaum at 1·3, Richardson at 2·8,[166] Morgan[167] at 3·4. In the American war of secession, in 11,000 operations, there were seven deaths--that is, 6·3 per 10,000, the highest number on a large scale which appears to be on record. In the ten years 1883-1892, 103 deaths are attributed to chloroform in England and Wales, viz., 88 deaths (57 males, 31 females) from accidents (no doubt in its use as a general anæsthetic), 14 (9 males, 5 females) from suicide, and a solitary case of murder.

[165] Chloroform: its Action, &c., London, 1865.

[166] Med. Times and Gazette, 1870.

[167] Med. Soc. of Virginia, 1872.

§ 184. =Suicidal and Criminal Poisoning by Chloroform.=--Suicidal poisoning by chloroform will generally be indicated by the surrounding circumstances; and in no case hitherto reported has there been any difficulty or obscurity as to whether the narcosis was self-induced or not. An interesting case is related by Schauenstein,[168] in which a physician resolved to commit suicide by chloroform, a commencing amaurosis having preyed upon his mind, and his choice having been determined by witnessing an accidental death by this agent. He accordingly plugged his nostrils, fitted on to the face an appropriate mask, and fastened it by strips of adhesive plaster. In such an instance, there could be no doubt of the suicidal intent, and the question of accident would be entirely out of the question.

[168] Maschka: Handbuch der gerichtlich. Medicin, p. 787, Tübingen, 1882.

A dentist in Potsdam,[169] in a state of great mental depression from embarrassed circumstances, killed his wife, himself, and two children by chloroform. Such crimes are fortunately very rare.

[169] Casper: Handbuch der ger. Med.

There is a vulgar idea that it is possible, by holding a cloth saturated with chloroform to the mouth of a sleeping person (or one, indeed, perfectly awake), to produce sudden insensibility; but such an occurrence is against all experimental and clinical evidence. It is true that a nervous person might, under such circumstances, faint and become insensible by mere nervous shock; but a true sudden narcosis is impossible.

Dolbeau has made some interesting experiments in order to ascertain whether, under any circumstances, a sleeping person might be anæsthetised. The main result appears to answer the question in the affirmative, at least with certain persons; but even with these, it can only be done by using the greatest skill and care, first allowing the sleeper to breathe very dilute chloroform vapour, and then gradually exhibiting stronger doses, and taking the cloth or inhaler away on the slightest symptom of approaching wakefulness. In 75 per cent. of the cases, however, the individuals awoke almost immediately on being exposed to the vapour. This cautious and scientific narcosis, then, is not likely to be used by the criminal class, or, if used, to be successful.

§ 185. =Physiological Effects.=--Chloroform is a protoplasmic poison. According to Jumelle, plants can even be narcotised, ceasing to assimilate and no longer being sensitive to the stimulus of light. Isolated animal cells, like leucocytes, lose through chloroform vapour their power of spontaneous movement, and many bacteria cease to multiply if in contact with chloroform water. According to Binx, chloroform narcosis in man is to be explained through its producing a weak coagulation of the cerebral ganglion cells. As already mentioned, chloroform has an affinity for the red blood-corpuscles. Chloroform stimulates the peripheral ends of the nerves of sensation, so that it causes irritation of the skin or mucous membranes when locally applied. Flourens considers that chloroform first affects the cerebrum, then the cerebellum, and finally the spinal cord; the action is at first stimulating, afterwards paralysing. Most anæsthetics diminish equally the excitability of the grey and the white nervous substance of the brain, and this is the case with chloroform, ether, and morphine; but apparently this is not the case with chloral hydrate, which only diminishes the conductivity of the cortical substance of the brain, and leaves the grey substance intact. Corresponding to the cerebral paralysis, the blood pressure sinks, and the heart beats slower and weaker.[170] The Hyderabad Commission made 735 researches on dogs and monkeys, and found that in fatal narcosis, so far as these animals are concerned, the respiration ceased before the heart, and this may be considered the normal mode of death; but it is probably going too far to say that it is the exclusive form of death in man, for there have been published cases in which the heart failed first.

[170] Kobert’s Lehrbuch der Intoxicationen.

§ 186. =Symptoms.=--There is but little outward difference between man and animals, in regard to the symptoms caused by breathing chloroform; in the former we have the advantage that the sensations preceding narcosis can be described by the individual.

The action of chloroform is usually divided into three more or less distinct stages. In the first there is a “drunken” condition, changes in the sense of smell and taste, and it may be hallucinations of vision and hearing; there are also often curious creeping sensations about the skin, and sometimes excessive muscular action, causing violent struggles. I have also seen epileptiform convulsions, and delirium is almost always present. The face during this stage is generally flushed, covered with perspiration, and the pupils contracted. The first stage may last from one minute to several, and passes into the second stage, or that of depression. Spontaneous movements cease, sensibility to all external stimuli vanishes, the patient falls into a deep sleep, the consciousness is entirely lost, and reflex movements are more and more annihilated. The temperature is less than normal, the respirations are slow, and the pulse is full and slow. The pupils in this stage are usually dilated, all the muscles are relaxed, and the limbs can be bent about in any direction. If now the inhalation of chloroform is intermitted, the patient wakes within a period which is usually from twenty to forty minutes, but may be several hours, after the last inhalation.

The third stage is that of paralysis; the pulse becomes irregular, the respirations superficial, there is a cyanotic colouring of the lips and skin, while the pupils become widely dilated. Death follows quickly through paralysis of the respiratory centre, the respirations first ceasing, then the pulse; in a few cases, the heart ceases first to beat.

According to Sansom’s facts,[171] in 100 cases of death by chloroform, 44·6 per cent. occurred before the full narcosis had been attained, that is in the first stage, 34·7 during the second stage, and 20·6 shortly after. So, also, Kappeler has recorded that in 101 cases of death from chloroform, 47·7 per cent. occurred before the full effect, and 52·2 during the full effect. This confirms the dictum of Billroth, that in all stages of anæsthesia by chloroform, death may occur. The quantity of chloroform, which, when inhaled in a given time, will produce death, is unknown; for all depends upon the greater or less admixture of air, and probably on other conditions. It has been laid down, that the inhalation of chloroform should be so managed as to insure that the air breathed shall never contain more than 3·9 per cent. of chloroform. Fifteen drops have caused death, but Taylor, on the other hand, records a case of tetanus, treated at Guy’s Hospital, in which no less a quantity than 700 grms. (22·5 ozs.) was inhaled in twenty-four hours. Frequent breathing of chloroform in no way renders the individual safe from fatal accident. A lady[172] having repeatedly taken chloroform, was anæsthetised by the same agent merely for the purpose of having a tooth extracted. About 6 grms. (1·5 drm.) were poured on a cloth, and after nine to ten inspirations, dangerous symptoms began--rattling breathing and convulsive movements--and, despite all remedies, she died.

[171] Op. cit.

[172] Edin. Med. Journ., 1855.

§ 187. Chronic chloroform poisoning is not unknown. It leads to various ailments, and seems to have been in one or two instances the cause of insanity.

Buchner records the case of an opium-eater, who afterwards took to chloroform; he suffered from periodic mania. In a remarkable case related by Meric, the patient, who had also first been a morphine-eater, took 350 grms. of chloroform in five days by inhalation; as often as he woke he would chloroform himself again to sleep. In this case, there was also mental disturbance, and instances in which chloroform produced marked mental aberration are recorded by Böhm[173] and by Vigla.[174]

[173] Ziemssen’s Handbuch, Bd. 15.

[174] Med. Times, 1855.

§ 188. =Post-mortem Appearances.=--The lesions found on section are neither peculiar to, nor characteristic of, chloroform poisoning. It has been noted that bubbles of gas are, from time to time, to be observed after death in the blood of those poisoned by chloroform, but it is doubtful whether the bubbles are not merely those to be found in any other corpse--in 189 cases, only eighteen times were these gas-bubbles observed,[175] so that, even if they are characteristic, the chances in a given case that they will not be seen are greater than the reverse. The smell of chloroform may be present, but has been noticed very seldom.

[175] Schauenstein (Op. cit.).

§ 189. =The detection and estimation of chloroform= from organic substances is not difficult, its low boiling-point causing it to distil readily. Accordingly (whatever may be the ultimate modifications, as suggested by different experimenters), the first step is to bring the substances, unless fluid, into a pulp with water, and submit this pulp to distillation by the heat of a water-bath. If the liquid operated upon possesses no particular odour, the chloroform may in this way be recognised in the distillate, which, if necessary, may be redistilled in the same manner, so as to concentrate the volatile matters in a small compass.

There are four chief tests for the identification of chloroform:--

(1.) The final distillate is tested with a little aniline, and an alcoholic solution of soda or potash lye; either immediately, or upon gently warming the liquid, there is a peculiar and penetrating odour of phenylcarbylamine, C₆H₅NC; it is produced by the following reaction:--

CHCl₃ + 3KOH + C₆H₅NH₂ = C₆H₅NC + 3KCl + 3H₂O.

Chloral, trichloracetic acid, bromoform and iodoform also give the same reaction; on the other hand, ethylidene chloride does not yield under these circumstances any carbylamine (isonitrile).

(2.) Chloroform reduces Fehling’s alkaline copper solution, when applied to a distillate, thus excluding a host of more fixed bodies which have the same reaction; it is a very excellent test, and may be made quantitative. The reaction is as follows:--

CHCl₃ + 5KHO + 2CuO = Cu₂O + K₂CO₃ + 3KCl + 3H₂O;

thus, every 100 parts of cuprous oxide equals 83·75 of chloroform.

(3.) The fluid to be tested (which, if acid, should be neutralised), is distilled in a slow current of hydrogen, and the vapour conducted through a short bit of red-hot combustion-tube containing platinum gauze. Under these circumstances, the chloroform is decomposed and hydrochloric acid formed; hence, the issuing vapour has an acid reaction to test-paper, and if led into a solution of silver nitrate, gives the usual precipitate of argentic chloride. Every 100 parts of silver chloride equal 27·758 of chloroform.

(4.) The fluid is mixed with a little thymol and potash; if chloroform be present, a reddish-violet colour is developed, becoming more distinct on the application of heat.[176]

[176] S. Vidali in Deutsch-Amerikan. Apoth.-Zeitung, vol. iij., Aug. 15, 1882.

§ 190. For the quantitative estimation of chloroform the method recommended by Schmiedeberg[177] is, however, the best. A combustion-tube of 24 to 26 cm. long, and 10 to 12 mm. in diameter, open at both ends, is furnished at the one end with a plug of asbestos, while the middle part, to within 5-6 cm. of the other end, is filled with pieces of caustic lime, from the size of a lentil to that of half a pea. The lime must be pure, and is made by heating a carbonate which has been precipitated from calcic nitrate. The other end of the tube is closed by a cork, carrying a silver tube, 16-18 cm. long, and 4 mm. thick. The end containing the asbestos plug is fitted by a cork to a glass tube. The combustion-tube thus prepared is placed in the ordinary combustion-furnace; the flask containing the chloroform is adapted, and the distillation slowly proceeded with. It is best to add a tube, bent at right angles and going to the bottom of the flask, to draw air continuously through the apparatus. During the whole process, the tube containing the lime is kept at a red heat. The chloroform is decomposed, and the chlorine combines with the lime. The resulting calcic chloride, mixed with much unchanged lime, is, at the end of the operation, cooled, dissolved in dilute nitric acid, and precipitated with silver nitrate. Any silver chloride is collected and weighed and calculated into chloroform.[178]

[177] Ueber die quantitative Bestimmung des Chloroforms im Blute. Inaug. Dissert., Dorpat, 1866.

[178] S. Vidali has made the ingenious suggestion of developing hydrogen in the usual way, by means of zinc and sulphuric acid, in the liquid supposed to contain chloroform, to ignite the hydrogen, as in Marsh’s test, when it issues from the tube, and then to hold in the flame a clean copper wire. Since any chloroform is burnt up in the hydrogen flame to hydrochloric acid, the chloride of copper immediately volatilises and colours the flame green.

VI.--Other Anæsthetics.

§ 191. When chlorine acts upon marsh-gas, the hydrogen can be displaced atom by atom; and from the original methane (CH₄) can be successively obtained chloromethane or methyl chloride (CH₃Cl), dichloromethane, or methene dichloride, methylene dichloride (CH₂Cl₂), trichloromethane, or chloroform (CHCl₃), already described, and carbon tetrachloride (CCl₄). All these are, more or less, capable of producing anæsthesia; but none of them, save chloroform, are of any toxicological importance.

Methene dichloride, recommended by Sir B. W. Richardson as an anæsthetic, has come somewhat into use. It is a colourless, very volatile liquid, of specific gravity 1·360, and boiling at 41°. It burns with a smoky flame, and dissolves iodine with a brown colour.

§ 192. =Pentane= (C₅H₁₂).--There are three isomers of pentane; that which is used as an anæsthetic is normal pentane, CH₃-CH₂-CH₂-CH₂-CH₃; its boiling-point is 37-38°. It is one of the constituents of petroleum ether.

Under the name of “Pental” it is used in certain hospitals extensively, for instance, at the Kaiser Friederich’s Children’s Hospital, Berlin.[179] It is stated to have no action on the heart.

[179] Zeit. f. Kinderheilk., Bd. iii.-iv., 1893.

One death[180] has been recorded from its use:--A lad, aged 14, was put under pental for the purpose of having two molars painlessly extracted. He was only a minute or two insensible, and 4-5 grms. of pental was the quantity stated to have been inhaled. The boy spat out after the operation, then suddenly fainted and died. The post-mortem showed œdema of the lungs; the right side of the heart was empty. The organs of the body smelled strongly of pental.

[180] Dr. Bremme, Vierteljahrsschr. f. gerichtliche Medicin, Bd. v., 1893.

§ 193. =Aldehyde= (Acetaldehyde), C₂H₄O =

O // CH₃-C , \ H

a fluid obtained by the careful oxidation of alcohol (boiling-point, 20·8°), is in large doses toxic; in smaller, it acts as a narcotic.

=Metaldehyde= (C₂H₄O₂)₂, obtained by treating acetaldehyde at a low temperature with hydrochloric acid. It occurs in the form of prisms, which sublime at about 112°; it is also poisonous.

§ 194. =Paraldehyde= (C₆H₁₂O₃) is a colourless fluid, boiling at 124°; specific gravity ·998 at 15°. By the action of cold it may be obtained in crystals, the melting point of which is 10·5°. It is soluble in eight parts of water at 13°; in warm water it is less soluble; hence, on warming a solution, it becomes turbid. Paraldehyde acts very similarly to chloral; it causes a deep sleep, and (judging by experiments on animals) produces no convulsive movements.

VII.--Chloral.

§ 195. =Chloral Hydrate= (C₂H₃Cl₃O₂) is made by mixing equivalent quantities of anhydrous chloral[181] and water. The purest chloral is in the form of small, granular, sugar-like crystals. When less pure, the crystals are larger. These melt into a clear fluid at from 48° to 49°, and the melted mass solidifies again at 48·9°. Chloral boils at 97·5°; it is not very soluble in cold chloroform, requiring four times its weight. The only substance with which chloral hydrate may well be confused is chloral alcoholate (C₄H₇Cl₃O₂), but chloral alcoholate melts at a lower temperature (45°), and boils at a higher (113·5°); it is easily soluble in cold chloroform, and inflames readily, whereas chloral scarcely burns.

[181] Anhydrous chloral (C₂HCl₃O) is an oily liquid, of specific gravity 1·502 at 18°; it boils at 97·7°. It is obtained by the prolonged action of chlorine on absolute alcohol.

Chloral hydrate completely volatilises, and can be distilled in a vacuum without change. If, however, boiled in air, it undergoes slow decomposition, the first portions of the distillate being overhydrated, the last underhydrated; the boiling-point, therefore, undergoes a continuous rise. The amount of hydration of a commercial sample is of practical importance; if too much water is present, the chloral deliquesces, especially in warm weather; if too little, it may become acid, and in part insoluble from the formation of meta-chloral (C₆H₃Cl₉O₃). Chloral hydrate, by the action of the volatile or fixed alkalies, is decomposed, an alkaline formiate and chloroform resulting thus--

C₂HCl₃O,H₂O + NaHO = NaCHO₂ + H₂O + CHCl₃.

Trichlor-acetic acid is decomposed in a similar manner.

=Statistics.=--Chloral caused, during the ten years 1883-1892 in England and Wales, 127 deaths--viz., 111 (89 males, 22 females) accidentally, 15 (14 males, 1 female) from suicide, and a case in which chloral was the agent of murder.

§ 196. =Detection.=--It is, of course, obvious that after splitting up chloral into chloroform, the latter can be detected by distillation and applying the tests given at p. 152 and seq. Chloral hydrate is soluble in one and a half times its weight of water; the solution should be perfectly neutral to litmus. It is also soluble in ether, in alcohol, and in carbon disulphide. It may be extracted from its solution by shaking out with ether. There should be no cloudiness when a solution is tested with silver nitrate in the cold; if, however, to a boiling solution nitrate of silver and a little ammonia are added, there is a mirror of reduced silver.

§ 197. The assay of chloral hydrate in solutions is best effected by distilling the solution with slaked lime; the distillate is received in water contained in a graduated tube kept at a low temperature. The chloroform sinks to the bottom, and is directly read off; the number of c.c. multiplied by 2·064 equals the weight of the chloral hydrate present.

Another method, accurate but only applicable to the fairly pure substance, is to dissolve 1 to 2 grms. in water, remove any free acid by baric carbonate, and then treat the liquid thus purified by a known volume of standard soda. The soda is now titrated back, using litmus as an indicator, each c.c. of normal alkali neutralised by the sample corresponds to 0·1655 grm. of chloral hydrate. Small quantities of chloral hydrate may be conveniently recovered from complex liquids by shaking them up with ether, and removing the ethereal layer, in the tube represented in the figure.[182] The ether must be allowed to evaporate spontaneously; but there is in this way much loss of chloral. The best method of estimating minute quantities is to alkalise the liquid, and slowly distil the vapour through a red-hot combustion-tube charged with pure lime, as in the process described at p. 153. A dilute solution of chloral may also be treated with a zinc-copper couple, the nascent hydrogen breaks the molecule up, and the resulting chloride may be titrated, as in water analyses, by silver nitrate and potassic chromate.

[182] The figure is from “Foods”; the description may be here repeated:--A is a tube of any dimensions most convenient to the analyst. Ordinary burette size will perhaps be the most suitable for routine work; the tube is furnished with a stopcock and is bent at B, the tube at K having a very small but not quite capillary bore. The lower end is attached to a length of pressure-tubing, and is connected with a small reservoir of mercury, moving up and down by means of a pulley. To use the apparatus: Fill the tube with mercury by opening the clamp at H, and the stopcock at B, and raising the reservoir until the mercury, if allowed, would flow out of the beak. Now, the beak is dipped into the liquid to be extracted with the solvent, and by lowering the reservoir, a strong vacuum is created, which draws the liquid into the tube; in the same way the ether is made to follow. Should the liquid be so thick that it is not possible to get it in by means of suction, the lower end of the tube is disconnected, and the syrupy mass worked in through the wide end. When the ether has been sucked into the apparatus, it is emptied of mercury by lowering the reservoir, and then firmly clamped at H, and the stopcock also closed. The tube may now be shaken, and then allowed to stand for the liquids to separate. When there is a good line of demarcation, by raising the reservoir after opening the clamp and stopcock, the whole of the light solvent can be run out of the tube into a flask or beaker, and recovered by distillation. For heavy solvents (such as chloroform), which sink to the bottom, a simple burette, with a fine exit tube is preferable; but for petroleum ether, ordinary ether, &c., the apparatus figured is extremely useful.

§ 198. =Effects of Chloral Hydrate on Animals.=--Experiments on animals have taught us all that is known of the physiological action of chloral. It has been shown that the drug influences very considerably the circulation, at first exciting the heart’s action, and then paralysing the automatic centre. The heart, as in animals poisoned by atropine, stops in diastole, and the blood-pressure sinks in proportion to the progressive paralysis of the cardiac centre. At the same time, the respiration is slowed and finally ceases, while the heart continues to beat. The body temperature of the warm-blooded animals is very remarkably depressed, according to Falck, even to 7·6°. Vomiting has been rather frequently observed with dogs and cats, even when the drug has been taken into the system by subcutaneous injection.

The secretion of milk, according to Röhrig, is also diminished. Reflex actions through small doses are intensified; through large, much diminished. ·025-·05 grm. (·4-·7 grain), injected subcutaneously into frogs, causes a slowing of the respiration, a diminution of reflex excitability, and lastly, its complete cessation; this condition lasts several hours; at length the animal returns to its normal state. If the dose is raised to ·1 grm. (1·5 grain) after the cessation of reflex movements, the heart is paralysed--and a paralysis not due to any central action of the vagus, but to a direct action on the cardiac ganglia. Rabbits of the ordinary weight of 2 kilos. are fully narcotised by the subcutaneous injection of 1 grm.; the sleep is very profound, and lasts several hours; the animal wakes up spontaneously, and is apparently none the worse. If 2 grms. are administered, the narcotic effects, rapidly developed, are much prolonged. There is a remarkable diminution of temperature, and the animal dies, the respiration ceasing without convulsion or other sign. Moderate-sized dogs require 6 grms. for a full narcosis, and the symptoms are similar; they also wake after many hours, in apparent good health.[183]

[183] C. Ph. Falck has divided the symptoms into (1) Preliminary hypnotic; (2) an adynamic state; and (3) a comatose condition.

§ 199. Liebreich considered that the action of chloral was due to its being broken up by the alkali of the blood, and the system being thus brought into a state precisely similar to its condition when anæsthetised by chloroform vapour. This view has, however, been proved to be erroneous. Chloral hydrate can, it is true, be decomposed in some degree by the blood at 40°; but the action must be prolonged for several hours. A 1 per cent. solution of alkali does not decompose chloral at a blood-heat in the time within which chloral acts in the body; and since narcotic effects are commonly observed when, in the fatty group, hydrogen has been displaced by chlorine, it is more probable that chloral hydrate is absorbed and circulates in the blood as such, and is not broken up into chloroform and an alkaline formiate.

§ 200. =Effects of Chloral Hydrate on Man.=--Since the year 1869, in which chloral was first introduced to medicine, it has been the cause of a number of accidental and other cases of poisoning. I find, up to the year 1884, recorded in medical literature, thirty-one cases of poisoning by chloral hydrate. This number is a small proportion only of the actual number dying from this cause. In nearly all the cases the poison was taken by the mouth, but in one instance the patient died in three hours, after having injected into the rectum 5·86 grms. of chloral hydrate. There is also on record a case in which, for the purpose of producing surgical anæsthesia, 6 grms. of chloral were injected into the veins; the man died in as many minutes.[184]

[184] This dangerous practice was introduced by M. Ore. In a case of traumatic tetanus, in which M. Ore injected into the veins 9 grms. of chloral in 10 grms. of water, there was profound insensibility, lasting eleven hours, during which time a painful operation on the thumb was performed. The next day 10 grms. were injected, when the insensibility lasted eight hours; and 9 grms. were injected on each of the two following days. The man recovered. In another case, Ore anæsthetised immediately a patient by plunging the subcutaneous needle of his syringe into the radial vein, and injected 10 grms. of chloral hydrate with 30 of water. The patient became insensible before the whole quantity was injected with “une immobilité rappellant celle du cadavre.” On finishing the operation, the patient was roused immediately by the application of an electric current, one pole on the left side of the neck, the other on the epigastrium. Journ. de Pharm. et de Chimie., t. 19, p. 314.

§ 201. =Fatal Dose.=--It is impossible to state with any exactness the precise quantity of chloral which may cause death. Children bear it better, in proportion, than adults, while old persons (especially those with weak hearts, and those inclined to apoplexy) are likely to be strongly affected by very small doses. A dose of ·19 grm. (3 grains) has been fatal to a child a year old in ten hours. On the other hand, according to Bouchut’s observations on 10,000 children, he considers that the full therapeutic effect of chloral can be obtained safely with them in the following ratio:--

Children of 1 to 3 years, dose 1 to 1·5 grm. (15·4 to 23·1 grains) „ 3 „ 5 „ „ 2 „ 3 „ (30·8 „ 46·3 „ ) „ 5 „ 7 „ „ 3 „ 4 „ (46·3 „ 61·7 „ )

These quantities being dissolved in 100 c.c. of water.

These doses are certainly too high, and it would be dangerous to take them as a guide, since death has occurred in a child, aged 5, from a dose of 3 grms. (46·3 grains). Medical men in England consider 20 grains a very full dose for a child of four years old, and 50 for an adult, while a case is recorded in which a dose of 1·9 grm. (30 grains) proved fatal in thirty-five hours to a young lady aged 20. On the other hand, we find a case[185] in which, to a patient suffering from epileptic mania, a dose of 31·1 grms. (1·1 oz.) of chloral hydrate was administered; she sank into a deep sleep in five minutes. Subcutaneous injections of strychnine were applied, and after sleeping for forty-eight hours, there was recovery. On the third day a vivid scarlatinal rash appeared, followed by desquamation. The examples quoted--the fatal dose of 1·9 grm., and recovery from 31 grms.--are the two extremes for adults. From other cases, it appears tolerably plain that most people would recover, especially with appropriate treatment, from a single dose under 8 grms., but anything above that quantity taken at one time would be very dangerous, and doses of 10 grms. and above, almost always fatal. If, however, 8 grms. were taken in divided doses during the twenty-four hours, it could (according to Sir B. W. Richardson) be done with safety. The time from the taking of the poison till death varies considerably, and is in part dependent on the dose.

[185] Chicago Medical Review, 1882.

In seven cases of lethal poisoning, three persons who took the small doses of 1·25, 2·5, and 1·95 grms. respectively, lived from eight to ten hours; two, taking 4 and 5 grms. respectively, died very shortly after the administration of the chloral. In a sixth case, related by Brown, in which 3·12 grms. had been taken, the patient lived an hour; and in another, after a dose of 5 grms., recorded by Jolly, death took place within a quarter of an hour.

§ 202. =Symptoms.=--With moderate doses there are practically no symptoms, save a drowsiness coming on imperceptibly, and followed by heavy sleep. With doses up to 2 grms. (30·8 grains), the hypnotic state is perfectly under the command of the will, and if the person chooses to walk about or engage in any occupation, he can ward off sleep; but with those doses which lead to danger, the narcosis is completely uncontrollable, the appearance of the sleeper is often strikingly like that of a drunken person. There is great diminution of temperature commencing in from five to twenty minutes after taking the dose--occasionally sleep is preceded by a delirious state. During the deep slumber the face is much flushed, and in a few cases the sleep passes directly into death without any marked change. In others, symptoms of collapse appear, and the patient sinks through exhaustion.

§ 203. With some persons doses, which, in themselves, are insufficient to cause death, yet have a peculiar effect on the mental faculties. A case of great medico-legal interest is described by the patient himself, Dr. Manjot.[186] He took in three doses, hourly, 12 grms. of chloral hydrate. After the first dose the pain, for which he had recourse to chloral, vanished; but Manjot, although he had all the appearance of being perfectly conscious, yet had not the slightest knowledge of what he was doing or speaking. He took the other two doses, and sank into a deep sleep which lasted twelve hours. He then awoke and answered questions with difficulty, but could not move; he lay for the next twelve hours in a half slumber, and the following night slept soundly--to wake up recovered.

[186] Gaz. des Hôp., 1875.

§ 204. The treatment of acute chloral poisoning which has been most successful is that by strychnine injections, and the application of warmth to counteract the loss of temperature which is so constant a phenomenon. As an illustration of the treatment by strychnine, an interesting case recorded by Levinstein[187] may be quoted.

[187] Vierteljahrsschr. f. ger. Med., Bd. xx., 1874.

A man, thirty-five years old, took at one dose, for the purpose of suicide, 24 grms. of chloral hydrate. In half an hour afterwards he was found in a deep sleep, with flushed face, swollen veins, and a pulse 160 in the minute. After a further half hour, the congestion of the head was still more striking; the temperature was 39·5°; the pulse hard and bounding 92; the breathing laboured, at times intermittent.

Artificial respiration was at once commenced, but in spite of this, in about another half hour, the face became deadly pale, the temperature sank to 32·9°. The pupils contracted, and the pulse was scarcely to be felt; 3 mgrms. (·04 grain) of strychnine were now injected subcutaneously; this caused tetanic convulsions in the upper part of the body and trismus. The heart’s action again became somewhat stronger, the temperature rose to 33·3°, and the pupils dilated; but soon followed, again, depression of the heart’s action, and the respiration could only be kept going by faradisation. Two mgrms. (·03 grain) of strychnine were once more injected, and the heart’s action improved. During the succeeding six hours the respiration had to be assisted by faradisation. The temperature gradually rose to 36·5°; ten hours after taking the dose the patient lay in a deep sleep, breathing spontaneously and reacting to external stimuli with a temperature of 38·5°. Eighteen hours from the commencement, the respiration again became irregular, and the galvanic current was anew applied. The last application aroused the sleeper, he took some milk and again slept; after twenty-seven hours he could be awakened by calling, &c., but had not full consciousness; he again took some milk and sank to sleep. It was not until thirty-two hours had elapsed from the ingestion of the poison that he awoke spontaneously; there were no after effects.

§ 205. =Chronic Poisoning by Chloral Hydrate.=--An enormous number of people habitually take chloral hydrate. The history of the habit is usually that some physician has given them a chloral prescription for neuralgia, for loss of sleep, or other cause, and finding that they can conjure sleep, oblivion, and loss (it may be) of suffering whenever they choose, they go on repeating it from day to day until it becomes a necessity of their existence. A dangerous facility to chloral-drinking is the existence of patent medicines, advertised as sleep-producers, and containing chloral as the active ingredient. A lady, aged 35, died in 1876, at Exeter, from an overdose of “Hunter’s solution of chloral, or sedative draught and sleep producer.” Its strength was stated at the inquest to be 25 grains to the drachm (41·6 per cent.).[188]

[188] Exeter and Plymouth Gazette, Jan. 12, 1876.

The evil results of this chloral-drinking are especially to be looked for in the mental faculties, and the alienists have had since 1869 a new insanity-producing factor. In the asylums may usually be found several cases of melancholia and mania referred rightly (or wrongly) to chloral-drinking. Symptoms other than cerebral are chilliness of the body, inclination to fainting, clonic convulsions, and a want of co-ordination of the muscles of the lower extremities. In a case recorded by Husband,[189] a lady, after twelve days’ treatment by chloral hydrate, in doses of from 1 to 2 grms. (15·4 to 30·8 grains), suffered from a scarlatina-like rash, which was followed by desquamation. Among the insane, it has also been noticed that its use has been followed by nettle-rash and petechiæ (Reimer and others).

[189] Lancet, 1871.

§ 206. =Excretion of Chloral.=--Chloral hydrate is separated in the urine partly as urochloral acid (C₈H₁₁Cl₃O₇). Butylchloral is separated as butyl urochloral acid (C₁₀H₁₅Cl₂O₇). Urochloral acid is crystalline, soluble in water, in alcohol, and in ether, reduces copper from Fehling’s solution, and rotates a ray of polarised light to the left. Urochloral acid, on boiling with either dilute sulphuric or hydrochloric acid, splits up into trichlorethyl alcohol and glycuronic acid--

C₈H₁₁Cl₃O₇ + H₂O = C₂H₃Cl₃O + C₆H₁₀O₇.

Trichloralcohol is an oily fluid (boiling-point 150°-152°); it yields by oxidation trichloracetic acid.

Urobutyl chloral acid gives on treatment with mineral acids trichlorbutyl alcohol and glycuronic acid.

To separate urochloral acid from the urine the following process has been found successful:--

The urine is evaporated to a syrup at the heat of the water-bath, and then strongly acidulated with sulphuric acid and repeatedly shaken out in a separating tube with a mixture of 3 vols. of ether and 1 vol. of alcohol. The ether-alcohol is separated and distilled off, the acid residue is neutralised with KHO, or potassic carbonate, and evaporated; the dry mass is then taken up with 90 per cent. alcohol, the filtrate precipitated with ether, and the precipitate washed with ether and absolute alcohol.

Next the precipitate is boiled with absolute alcohol and filtered hot. On cooling, the potassium salt of urochloral acid separates out in tufts of silky needles. The crystals are dried over sulphuric acid and again washed several times with absolute alcohol and ether to remove impurities.

To obtain the free acid, the potassium salt is dissolved in a little water and acidulated with hydrochloric acid; the liquid is then shaken out in a separating tube, with a mixture of 8 vols. of ether and 1 of alcohol. The ether-alcohol is distilled off, the residue treated with moist silver oxide until no farther separation of silver chloride occurs, the silver chloride is separated by filtration, the soluble silver salt decomposed by SH₂, and the filtrate carefully evaporated to a syrup; after a few hours, the acid crystallises in stars of needles.

Urobutylchloral acid can be obtained in quite a similar way.[190]

[190] V. Mering u. Musculus, Ber., viii. 662; v. Mering, ibid., xv. 1019; E. Kulz, Ber., xv., 1538.

§ 207. =Separation of Chloral from Organic Matters.=--It will be most convenient to place the organic fluid or pulped-up solid, mixed with water, in a retort, to acidify with tartaric acid, and to distil.

Chloral hydrate distils over from a liquid acidified with tartaric acid; to obtain the whole of the chloral requires distillation in a vacuum almost to dryness.

The distillation will, unless there is also some partly decomposed chloral, not smell of chloroform, and yet give chloroform reactions.

To identify it, to the distillate should be added a little burnt magnesia, and the distillate thus treated boiled for half an hour in a flask connected with an inverted condenser; in this way the chloral hydrate is changed into chloroform and magnesium formate--

2CCl₃CH(OH)₂ + MgO = 2CHCl₃ + (HCOO)₂Mg + H₂O.

The fluid may now be tested for formic acid: it will give a black precipitate with solution of silver nitrate--

(HCOO)₂Mg + 4AgNO₃ = 4Ag + Mg(NO₃)₂ + 2CO₂ + 2HNO₃.

It will give a white precipitate of calomel when treated with mercuric chloride solution--

(HCOO)₂Mg + 4HgCl₂ = 2Hg₂Cl₂ + MgCl₂ + 2HCl + 2CO₂.

Chloral (or chloroform), when boiled with resorcinol and the liquid made strongly alkaline with NaHO, gives a red colour, which disappears on acidifying and is restored by alkalies. If, on the other hand, there is an excess of resorcinol and only a very small quantity of NaHO used, the product shows a yellowish-green fluorescence; 1/10 of a milligramme of chloral hydrate gives this reaction distinctly when boiled with 50 mgrms. of resorcinol and 5 drops of a normal solution of sodium hydrate.[191]

[191] C. Schwarz, Pharm. Zeit., xxxiii. 419.

Dr. Frank Ogston[192] has recommended sulphide of ammonium to be added to any liquid as a test for chloral. The contents of the stomach are filtered or submitted to dialysis, and the test applied direct. If chloral is present, there is first an orange-yellow colour; on standing, the fluid becomes more and more brown, then troubled, an amorphous precipitate falls to the bottom, and a peculiar odour is developed. With 10 mgrms. of chloral in 1 c.c. of water, there is an evident precipitate, and the odour can readily be perceived; with 1 mgrm. dissolved in 1 c.c. of water, there is an orange-yellow colour, and also the odour, but no precipitate; with ·1 mgrm. in 1 c.c. of water, there is a weak, pale, straw-yellow colour, which can scarcely be called characteristic. The only substance giving in neutral solutions the same reactions is antimony; but, on the addition of a few drops of acid, the antimony falls as an orange-yellow precipitate, while, if chloral alone is present, there is a light white precipitate of sulphur.

[192] Vierteljahrsschrift f. gerichtl. Medicin, 1879, Bd. xxx. Hft. 1, S. 268.

VIII.--Bisulphide of Carbon.

§ 208. Bisulphide of carbon--carbon disulphide, carbon sulphide (CS₂)--is a colourless, volatile fluid, strongly refracting light. Commercial samples have a most repulsive and penetrating odour, but chemically pure carbon sulphide has a smell which is not disagreeable. The boiling-point is 47°; the specific gravity at 0° is 1·293. It is very inflammable, burning with a blue flame, and evolving sulphur dioxide; is little soluble in water, but mixes easily with alcohol or ether. Bisulphide of carbon, on account of its solvent powers for sulphur, phosphorus, oils, resins, caoutchouc, gutta-percha, &c., is in great request in certain industries. It is also utilised for disinfecting purposes, the liquid being burnt in a lamp.

§ 209. =Poisoning by Carbon Bisulphide.=--In spite of the cheapness and numerous applications of this liquid, poisoning is very rare. There appears to be a case on record of attempted self-destruction by this agent, in which a man took 2 ozs. (56·7 c.c.) of the liquid, but without a fatal result. The symptoms in this case were pallor of the face, wide pupils, frequent and weak pulse, lessened bodily temperature, and spasmodic convulsions. Carbon disulphide was detected in the breath by leading the expired air through an alcoholic solution of triethyl-phosphin, with which it struck a red colour. It could also be found in the urine in the same way. An intense burning in the throat, giddiness, and headache lasted for several days.

§ 210. Experiments on animals have been frequent, and it is found to be fatal to all forms of animal life. There is, indeed, no more convenient agent for the destruction of various noxious insects, such as moths, the weevils in biscuits, the common bug, &c., than bisulphide of carbon. It has also been recommended for use in exterminating mice and rats.[193] Different animals show various degrees of sensitiveness to the vapour; frogs and cats being less affected by it than birds, rabbits, and guinea-pigs. It is a blood poison; methæmoglobin is formed, and there is disintegration of the red blood corpuscles. There is complete anæsthesia of the whole body, and death occurs through paralysis of the respiratory centre, but artificial respiration fails to restore life.

[193] Cloëz, Compt. Rend., t. 63, 85.

§ 211. =Chronic Poisoning.=--Of some importance is the chronic poisoning by carbon disulphide, occasionally met with in manufactures necessitating the daily use of large quantities for dissolving caoutchouc, &c. When taken thus in the form of vapour daily for some time, it gives rise to a complex series of symptoms which may be divided into two principal stages--viz., a stage of excitement and one of depression. In the first phase, there is more or less permanent headache, with considerable indigestion, and its attendant loss of appetite, nausea, &c. The sensitiveness of the skin is also heightened, and there are curious sensations of creeping, &c. The mind at the same time in some degree suffers, the temper becomes irritable, and singing in the ears and noises in the head have been noticed. In one factory a workman suffered from an acute mania, which subsided in two days upon removing him from the noxious vapour (Eulenberg). The sleep is disturbed by dreams, and, according to Delpech,[194] there is considerable sexual excitement, but this statement has in no way been confirmed. Pains in the limbs are a constant phenomenon, and the French observers have noticed spasmodic contractions of certain groups of muscles.

[194] Mémoire sur les Accidents que développe chez les ouvrières en caoutchouc du sulfure de carb. en vapeur, Paris, 1856.

The stage of depression begins with a more or less pronounced anæsthesia of the skin. This is not confined to the outer skin, but also affects the mucous membranes; patients complain that they feel as if the tongue were covered with a cloth. The anæsthesia is very general. In a case recorded by Bernhardt,[195] a girl, twenty-two years old, who had worked six weeks in a caoutchouc factory, suffered from mental weakness and digestive troubles; there was anæsthesia and algesis of the whole skin. In these advanced cases the mental debility is very pronounced, and there is also weakness of the muscular system. Paralysis of the lower limbs has been noted, and in one instance a man had his right hand paralysed for two months. It seems uncertain how long a person is likely to suffer from the effects of the vapour after he is removed from its influence. If the first stage of poisoning only is experienced, then recovery is generally rapid; but if mental and muscular weakness and anæsthesia of the skin have been developed, a year has been known to elapse without any considerable improvement, and permanent injury to the health may be feared.

[195] Ber. klin. Wochenschrift, No. 32, 1866.

§ 212. =Post-mortem Appearances.=--The pathological appearances found after sudden death from disulphide of carbon are but little different to those found after fatal chloroform breathing.

§ 213. =Detection and Separation of Carbon Disulphide.=--The extreme volatility of the liquid renders it easy to separate it from organic liquids by distillation with reduced pressure in a stream of CO₂. Carbon disulphide is best identified by (1) Hofman’s test, viz., passing the vapour into an ethereal solution of triethyl-phosphin, (C₂H₅)₃P. Carbon disulphide forms with triethyl-phosphin a compound which crystallises in red scales. The crystals melt at 95° C., and have the following formula--P(C₂H₅)₃CS₂. This will detect 0·54 mgrm. Should the quantity of bisulphide be small, no crystals may be obtained, but the liquid will become of a red colour. (2) CS₂ gives, with an alcoholic solution of potash, a precipitate of potassic xanthate, CS₂C₂H₅OK.

§ 214. =Xanthogenic acid or ethyloxide-sulphocarbonate= (CS₂C₂H₅OH) is prepared by decomposing potassic xanthogenate by diluted hydrochloric or sulphuric acid. It is a colourless fluid, having an unpleasant odour, and a weakly acid and rather bitter taste. It burns with a blue colour, and is easily decomposed at 24°, splitting up into ethylic alcohol and hydric sulphide. It is very poisonous, and has an anæsthetic action similar to bisulphide of carbon. Its properties are probably due to CS₂ being liberated within the body.

§ 215. =Potassic xanthogenate= (CS₂C₂H₅OK) and =potassic xanthamylate= (CS₂C₅H₁₁OK) (the latter being prepared by the substitution of amyl alcohol for ethyl alcohol), both on the application of a heat below that of the body, develop CS₂, and are poisonous, inducing symptoms very similar to those already detailed.

IX.--The Tar Acids--Phenol--Cresol.

§ 216. =Carbolic Acid. Syn. Phenol, Phenyl Alcohol, Phenylic Hydrate; Phenic Acid; Coal-Tar Creasote.=--The formula for carbolic acid is C₆H₅HO. The pure substance appears at the ordinary temperature as a colourless solid, crystallising in long prisms; the fusibility of the crystals is given variously by different authors: from my own observation, the pure crystals melt at 40°-41°, any lower melting-point being due to the presence of cresylic acid or other impurity; the crystals again become solid about 15°. Melted carbolic acid forms a colourless limpid fluid, sinking in water. It boils under the ordinary pressure at 182°, and distils without decomposition; it is very readily and completely distilled in a vacuum at about the temperature of 100°. After the crystals have been exposed to the air, they absorb water, and a hydrate is formed containing 16·07 per cent. of water. The hydrate melts at 17°, any greater hydration prevents the crystallisation of the acid; a carbolic acid, containing about 27 per cent. of water, and probably corresponding to the formula C₆H₆O,2H₂O, is obtained by gradually adding water to carbolic acid so long as it continues to be dissolved. Such a hydrate dissolves in 11·1 times its measure of water, and contains 8·56 per cent. of real carbolic acid. Carbolic acid does not redden litmus, but produces a greasy stain on paper, disappearing on exposure to the air; it has a peculiar smell, a burning numbing taste, and in the fluid state it strongly refracts light. Heated to a high temperature it takes fire, and burns with a sooty flame.

When an aqueous solution of carbolic acid is shaken up with ether, benzene, carbon disulphide, or chloroform, it is fully dissolved by the solvent, and is thus easily separated from most solutions in which it exists in the free state. Petroleum ether, on the other hand, only slightly dissolves it in the cold, more on warming. Carbolic acid mixes in all proportions with glycerin, glacial or acetic acid, and alcohol. It coagulates albumen, the precipitate being soluble in an excess of albumen; it also dissolves iodine, without changing its properties. It dissolves many resins, and also sulphur, but, on boiling, sulphuretted hydrogen is disengaged. Indigo blue is soluble in hot carbolic acid, and may be obtained in crystals on cooling. Carbolic acid is contained in castoreum, a secretion derived from the beaver, but it has not yet been detected in the vegetable kingdom. The source of carbolic acid is at present coal-tar, from which it is obtained by a process of distillation. There are, however, a variety of chemical actions in the course of which carbolic acid is formed.

§ 217. The common disinfecting carbolic acid is a dark reddish liquid, with a very strong odour; at present there is very little phenol in it; it is mainly composed of meta- and para-cresol. It is officinal in Germany, and there must contain at least 50 per cent. of the pure carbolic acid. The pure crystallised carbolic acid is officinal in our own and all the continental pharmacopœias. In the British Pharmacopœia, a solution of carbolic acid in glycerin is officinal; the proportions are 1 part of carbolic acid and 4 parts of glycerin, that is, strength by measure = 20 per cent. The Pharmacopœia Germanica has a liquor natri carbolici, made with 5 parts carbolic acid, 1 caustic soda, and 4 of water; strength in carbolic acid = 50 per cent. There is also a strongly alkaline crude sodic carbolate in use as a preservative of wood.

There are various disinfecting fluids containing amounts of carbolic acid, from 10 per cent. upwards. Many of these are somewhat complex mixtures, but, as a rule, any poisonous properties they possess are mainly due to their content of phenol or cresol. A great variety of disinfecting powders, under various names, are also in commerce, deriving their activity from carbolic acid. Macdougall’s disinfecting powder is made by adding a certain proportion of impure carbolic acid to a calcic sulphite, which is prepared by passing sulphur dioxide over ignited limestone.

=Calvert’s carbolic acid powder= is made by adding carbolic acid to the siliceous residue obtained from the manufacture of aluminic sulphate from shale. There are also various carbolates which, by heating or decomposing with sulphuric acid, give off carbolic acid.

=Carbolic acid soaps= are also made on a large scale--the acid is free, and some of the soaps contain as much as 10 per cent. In the inferior carbolic acid soaps there is little or no carbolic acid, but cresylic takes its place. Neither the soaps nor the powders have hitherto attained any toxicological importance, but the alkaline carbolates are very poisonous.

§ 218. =The chief uses= of carbolic acid are indicated by the foregoing enumeration of the principal preparations used in medicine and commerce. The bulk of the carbolic acid manufactured is for the purposes of disinfection. It is also utilised in the preparation of certain colouring matters or dyes, and during the last few years has had another application in the manufacture of salicylic acid. In medicine it is administered occasionally internally, while the antiseptic movement in surgery, initiated by Lister, has given it great prominence in surgical operations.

§ 219. =Statistics.=--The tar acids, i.e., pure carbolic acid and the impure acids sold under the name of carbolic acid, but consisting (as stated before) mainly of cresol, are, of all powerful poisons, the most accessible, and the most recklessly distributed. We find them at the bedside of the sick, in back-kitchens, in stables, in public and private closets and urinals, and, indeed, in almost all places where there are likely to be foul odours or decomposing matters. It is, therefore, no wonder that poisoning by carbolic acid has, of late years, assumed large proportions. The acid has become vulgarised, and quite as popularly known, as the most common household drugs or chemicals.[196] This familiarity is the growth of a very few years, since it was not discovered until 1834, and does not seem to have been used by Lister until about 1863. It was not known to the people generally until much later. At present it occupies the third place in fatality of all poisons in England. The following table shows that, in the past ten years, carbolic acid has killed 741 people, either accidentally or suicidally; there is also one case of murder by carbolic acid within the same period, bringing the total up to 742:--

[196] Although this is so, yet much ignorance still prevails as to its real nature. In a case reported in the Pharm. Journ., 1881, p. 334, a woman, thirty years of age, drank two-thirds of an ounce of liquid labelled “Pure Carbolic Acid” by mistake, and died in two hours. She read the label, and a lodger also read it, but did not know what it meant.

DEATHS FROM CARBOLIC ACID IN ENGLAND AND WALES DURING THE TEN YEARS ENDING 1892.

ACCIDENT OR NEGLIGENCE.

Ages, 0-1 1-5 5-15 15-25 25-65 65 and Total above Males, 2 39 13 5 83 8 150 Females, 2 21 7 13 51 7 101 ------------------------------------------- Totals, 4 60 20 18 134 15 251 -------------------------------------------

SUICIDE.

Ages, 15-25 25-65 65 and Total above Males, 26 186 7 219 Females, 72 194 5 271 ---------------------------- Totals, 98 380 12 490 ----------------------------

Falck has collected, since the year 1868, no less than 87 cases of poisoning from carbolic acid recorded in medical literature. In one of the cases the individual died in nine hours from a large dose of carbolate of soda; in a second, violent symptoms were induced by breathing for three hours carbolic acid vapour; in the remaining 85, the poisoning was caused by the liquid acid. Of these 85 persons, 7 had taken the poison with suicidal intent, and of the 7, 5 died; 39 were poisoned through the medicinal use of carbolic acid, 27 of the 39 by the antiseptic treatment of wounds by carbolic acid dressings, and of these 8 terminated fatally; in 8 cases, symptoms of poisoning followed the rubbing or painting of the acid on the skin for the cure of scabies, favus, or psoriasis, and 6 of these patients died. In 4 cases, carbolic acid enemata, administered for the purpose of dislodging ascarides, gave rise to symptoms of poisoning, and in one instance death followed.

The substitution of carbolic acid for medicine happened as follows:--

Cases. Taken instead of Tincture of Opium, 1 „ „ Infusion of Senna, 3 „ „ Mineral Water, 2 „ „ other Mixtures, 3 „ inwardly instead of applied outwardly, 3 -- 12

Of these 12, 8 died.

Again, 10 persons took carbolic acid in mistake for various alcoholic drinks, such as schnapps, brandy, rum, or beer, and 9 of the 10 succumbed; 17 persons drank carbolic acid simply “by mistake,” and of these 13 died. Thus, of the whole 85 cases, no less than 51 ended fatally--nearly 60 per cent.

It must be always borne in mind that, with regard to statistics generally, the term “carbolic acid” is not used by coroners, juries, or medical men, in a strictly chemical sense, the term being made to include disinfecting fluids which are almost wholly composed of the cresols, and contain scarcely any phenol. In this article, with regard to symptoms and pathological appearances, it is only occasionally possible to state whether the pure medicinal crystalline phenol or a mixture of tar-acids was the cause of poisoning.

§ 220. =Fatal Dose.=--The minimum fatal dose for cats, dogs, and rabbits, appears to be from ·4 to ·5 grm. per kilogram. Falck has put the minimum lethal dose for man at 15 grms. (231·5 grains), which would be about ·2 per kilo., basing his estimate on the following reasoning. In 33 cases he had a fairly exact record of the amount of acid taken, and out of the 33, he selects only those cases which are of use for the decision of the question. Among adults, in 5 cases the dose was 30 grms., and all the 5 cases terminated by death, in times varying from five minutes to an hour and a half. By other 5 adults a dose of 15 grms. was taken; of the 5, 3 men and a woman died, in times varying from forty-five minutes to thirty hours, while 1 woman recovered. Doses of 11·5, 10·8, and 9 grms. were taken by different men, and recovered from; on the other hand, a suicide who took one and a half teaspoonful (about 6 grms.) of the concentrated acid, died in fifty minutes. Doses of ·3 to 3 grms. have caused symptoms of poisoning, but the patients recovered, while higher doses than 15 grms. in 12 cases, with only one exception, caused death. Hence, it may be considered tolerably well established, that 15 grms. (231·5 grains) may be taken as representing the minimum lethal dose.

The largest dose from which a person appears to have recovered is, I believe, that given in a case recorded by Davidson, in which 150 grms. of crude carbolic acid had been taken. It must, however, be remembered that, as this was the impure acid, probably only half of it was really carbolic acid. The German Pharmacopœia prescribes as a maximum dose ·05 grm (·7 grain) of the crystallised acid, and a daily maximum quantity given in divided doses of ·15 grm. (2·3 grains).

§ 221. =Effects on Animals.=--Carbolic acid is poisonous to both animal and vegetable life.

=Infusoria.=--One part of the acid in 10,000 parts of water rapidly kills ciliated animalcules,--the movements become sluggish, the sarcode substance darker, and the cilia in a little time cease moving.

=Fish.=--One part of the acid in 7000 of water kills dace, minnows, roach, and gold fish. In this amount of dilution the effect is not apparent immediately; but, at the end of a few hours, the movements of the fish become sluggish, they frequently rise to the surface to breathe, and at the end of twenty-four hours are found dead. Quantities of carbolic acid, such as 1 part in 100,000 of water, appear to affect the health of fish, and render them more liable to be attacked by the fungus growth which is so destructive to fish-life in certain years.

=Frogs.=--If ·01 to ·02 grm. of carbolic acid be dissolved in a litre of water in which a frog is placed, there is almost immediately signs of uneasiness in the animal, showing that pain from local contact is experienced; a sleepy condition follows, with exaltation of reflex sensibility; convulsions succeed, generally, though not always; then reflex sensibility is diminished, ultimately vanishes, and death occurs; the muscles and nerves still respond to the electric current, and the heart beats, but slowly and weakly, for a little after the respiration has ceased.

§ 222. =Warm-blooded Animals.=--For a rabbit of the average weight of 2 kilos., ·15 grm. is an active dose, and ·3 a lethal dose (that is ·15 per kilo.). The sleepy condition of the frog is not noticed, and the chief symptoms are clonic convulsions with dilatation of the pupils, the convulsions passing into death, without a noticeable paralytic stage. The symptoms observed in poisoned dogs are almost precisely similar, the dose, according to body-weight, being the same. It has, however, been noticed that with doses large enough to produce convulsions, a weak condition has supervened, causing death in several days. There appears to be no cumulative action, since equal toxic doses can be given to animals for some time, and the last dose has no greater effect than the first or intermediate ones. The pathological appearances met with in animals poisoned by the minimum lethal doses referred to are not characteristic; but there is a remarkable retardation of putrefaction.

§ 223. =Symptoms in Man, external application.=--A 5 per cent. solution of carbolic acid, applied to the skin, causes a peculiar numbness, followed, it may be, by irritation. Young subjects, and those with sensitive skins, sometimes exhibit a pustular eruption, and concentrated solutions cause more or less destruction of the skin. Lemaire[197] describes the action of carbolic acid on the skin as causing a slight inflammation, with desquamation of the epithelium, followed by a very permanent brown stain, but this he alone has observed. Applied to the mucous membrane, carbolic acid turns the epithelial covering white; the epithelium, however, is soon thrown off, and the place rapidly heals; there is the same numbing, aconite-like feeling before noticed. The vapour of carbolic acid causes redness of the conjunctivæ, and irritation of the air-passages. If the application is continued, the mucous membrane swells, whitens, and pours out an abundant secretion.

[197] Lemaire, Jul., “De l’Acide phénique,” Paris, 1864.

Dr. Whitelock, of Greenock, has related two instances in which children were treated with carbolic acid lotion (strength 2½ per cent.) as an application to the scalp for ringworm; in both, symptoms of poisoning occurred--in the one, the symptoms at once appeared; in the other they were delayed some days. In order to satisfy his mind, the experiment was repeated twice, and each time gastric and urinary troubles followed.

Nussbaum, of Munich, records a case[198] in which symptoms were induced by the forcible injection of a solution of carbolic acid into the cavity of an abscess.

[198] Leitfaden zur antiseptischer Wundbehandlung, 141.

Macphail[199] gives two cases of poisoning by carbolic acid from external use. In the one, a large tumour had been removed from a woman aged 30, and the wound covered with gauze steeped in a solution of carbolic acid, in glycerin, strength 10 per cent.; subsequently, there was high fever, with diminished sulphates in the urine, which smelt strongly of carbolic acid, and was very dark. On substituting boracic acid, none of these troubles were observed. The second case was that of a servant suffering from axillary abscess; the wound was syringed out with carbolic acid solution, of strength 2½ per cent., when effects were produced similar to those in the first case. It was noted that in both these cases the pulse was slowed. Scattered throughout surgical and medical literature, there are many other cases recorded, though not all so clear as those cited. Several cases are also on record in which poisonous symptoms (and even death) have resulted from the application of carbolic acid lotion as a remedy for scabies or itch.

[199] “Carbolic Acid Poisoning (Surgical),” by S. Rutherford Macphail, M.B., Ed. Med. Journal, cccxiv., Aug. 1881, p. 134.

A surgeon prescribed for two joiners who suffered from scabies a lotion, which was intended to contain 30 grms. of carbolic acid in 240 c.c. of water; but the actual contents of the flasks were afterwards from analysis estimated by Hoppe-Seyler to be 33·26 grms., and the quantity used by each to be equal to 13·37 grms. (206 grains) of carbolic acid. One of the men died; the survivor described his own symptoms as follows:--He and his companion stood in front of the fire, and rubbed the lotion in; he rubbed it into his legs, breast, and the front part of his body; the other parts were mutually rubbed. Whilst rubbing his right arm, and drying it before the fire, he felt a burning sensation, a tightness and giddiness, and mentioned his sensations to his companion, who laughed. This condition lasted from five to seven minutes, but he did not remember whether his companion complained of anything, nor did he know what became of him, nor how he himself came to be in bed. He was found holding on to the joiner’s bench, looking with wide staring eyes, like a drunken man, and was delirious for half an hour. The following night he slept uneasily and complained of headache and burning of the skin. The pulse was 68, the appearance of the urine, appetite, and sense of taste were normal; the bowels confined. He soon recovered.

The other joiner seems to have died as suddenly as if he had taken prussic acid. He called to his mother, “Ich habe einen Rausch,” and died with pale livid face, after taking two deep, short inspirations.

The post-mortem examination showed the sinuses filled with much fluid blood, and the vessels of the pia mater congested. Frothy, dark, fluid blood was found in the lungs, which were hyperæmic; the mucous tissues of the epiglottis and air-tubes were reddened, and covered with a frothy slime. Both ventricles--the venæ cavæ and the vessels of the spleen and kidneys--were filled with dark fluid blood. The muscles were very red; there was no special odour. Hoppe-Seyler recognised carbolic acid in the blood and different organs of the body.[200]

[200] R. Köhler, Würtem. Med. Corr. Bl., xlii., No. 6, April 1872; H. Abelin, Schmidt’s Jahrbücher, 1877, Bd. 173, S. 163.

In another case, a child died from the outward use of a 2 per cent. solution of carbolic acid. It is described as follows:--An infant of seven weeks old suffered from varicella, and one of the pustules became the centre of an erysipelatous inflammation. To this place a 2 per cent. solution of carbolic acid was applied by means of a compress steeped in the acid; the following morning the temperature rose from 36·5° (97·7° F.) to 37° (98·6° F.), and poisonous symptoms appeared. The urine was coloured dark. There were sweats, vomitings, and contracted pupils, spasmodic twitchings of the eyelids and eyes, with strabismus, slow respiration, and, lastly, inability to swallow. Under the influence of stimulating remedies the condition temporarily improved, but the child died twenty-three and a half hours after the first application. An examination showed that the vessels of the brain and the tissue of the lungs were abnormally full of blood. The liver was softer than natural, and exhibited a notable yellowishness in the centre of the acini. Somewhat similar appearances were noticed in the kidneys, the microscopic examination of which showed the tubuli contorti enlarged and filled with fatty globules. In several places the epithelium was denuded, in other places swollen, and with the nuclei very visible.

In an American case,[201] death followed the application of carbolic acid to a wound. A boy had been bitten by a dog, and to the wound, at one o’clock in the afternoon, a lotion, consisting of nine parts of carbolic acid and one of glycerin, was applied. At seven o’clock in the evening the child was unconscious, and died at one o’clock the following day.

[201] American Journal of Pharmacy, vol. li., 4th Ser.; vol. ix., 1879, p. 57.

§ 224. =Internal Administration.=--Carbolic acid may be taken into the system, not alone by the mouth, but by the lungs, as in breathing carbolic acid spray or carbolic acid vapour. It is also absorbed by the skin when outwardly applied, or in the dressing or the spraying of wounds with carbolic acid. Lastly, the ordinary poisonous effects have been produced by absorption from the bowel, when administered as an enema. When swallowed undiluted, and in a concentrated form, the symptoms may be those of early collapse, and speedy death. Hence, the course is very similar to that witnessed in poisoning by the mineral acids.

If lethal, but not excessive doses of the diluted acid are taken, the symptoms are--a burning in the mouth and throat, a peculiarly unpleasant persistent taste, and vomiting. There is faintness with pallor of the face, which is covered by a clammy sweat, and the patient soon becomes unconscious, the pulse small and thready, and the pupils sluggish to light. The respiration is profoundly affected; there is dyspnœa, and the breathing becomes shallow. Death occurs from paralysis of the respiratory apparatus, and the heart is observed to beat for a little after the respiration has ceased. All these symptoms may occur from the application of the acid to the skin or to mucous membranes, and have been noticed when solutions of but moderate strength have been used--e.g., there are cases in gynæcological practice in which the mucous membrane (perhaps eroded) of the uterus has been irrigated with carbolic acid injections. Thus, Küster[202] relates a case in which, four days after confinement, the uterus was washed out with a 2 per cent. solution of carbolic acid without evil result. Afterwards a 5 per cent. solution was used, but it at once caused violent symptoms of poisoning, the face became livid, clonic convulsions came on, and at first loss of consciousness, which after an hour returned. The patient died on the ninth day. There was intense diphtheria of the uterus and vagina. Several other similar cases (although not attended with such marked or fatal effects) are on record.[203]

[202] Centralblatt. f. Gynäkologie, ii. 14, 1878.

[203] A practitioner in Calcutta injected into the bowel of a boy, aged 5, an enema of diluted carbolic acid, which, according to his own statement, was 1 part in 60, and the whole quantity represented 144 grains of the acid. The child became insensible a few minutes after the operation, and died within four hours. There was no post-mortem examination; the body smelt strongly of carbolic acid.--Lancet, May 19, 1883.

§ 225. The symptoms of carbolic acid poisoning admit of considerable variation from those already described. The condition is occasionally that of deep coma. The convulsions may be general, or may affect only certain groups of muscles. Convulsive twitchings of the face alone, and also muscular twitchings only of the legs, have been noticed. In all cases, however, a marked change occurs in the urine. Subissi[204] has noted the occurrence of abortion, both in the pig and the mare, as a result of carbolic acid, but this effect has not hitherto been recorded in the human subject.

[204] L’Archivio della Veterinaria Ital., xi., 1874.

It has been experimentally shown by Küster, that previous loss of blood, or the presence of septic fever, renders animals more sensitive to carbolic acid. It is also said that children are more sensitive than adults.

The course of carbolic acid poisoning is very rapid. In 35 cases collected by Falck, in which the period from the taking of the poison to the moment of death was accurately noted, the course was as follows:--12 patients died within the first hour, and in the second hour 3; so that within two hours 15 died. Between the third and the twelfth hour, 10 died; between the thirteenth and the twenty-fourth hour, 7 died; and between the twenty-fifth and the sixtieth hour, only 3 died. Therefore, slightly over 71 per cent. died within twelve hours, and 91·4 per cent. within the twenty-four hours.

§ 226. =Changes in the Urine.=--The urine of patients who have absorbed in any way carbolic acid is dark in colour, and may smell strongly of the acid. It is now established--chiefly by the experiments and observations of Baumann[205]--that carbolic acid, when introduced into the body, is mainly eliminated in the form of phenyl-sulphuric acid, C₆H₅HSO₄, or more strictly speaking as potassic phenyl-sulphate, C₆H₅KSO₄, a substance which is not precipitated by chloride of barium until it has been decomposed by boiling with a mineral acid. Cresol is similarly excreted as cresol-sulphuric acid, C₆H₄CH₃HSO₄, ortho-, meta-, or para-, according to the kind of cresol injected; a portion may also appear as hydro-tolu-chinone-sulphuric acid. Hence it is that, with doses of phenol or cresol continually increasing, the amount of sulphates naturally in the urine (as estimated by simply acidifying with hydrochloric acid, and precipitating in the cold with chloride of barium) continually decreases, and may at last vanish, for all the sulphuric acid present is united with the phenol. On the other hand, the precipitate obtained by prolonged boiling of the strongly acidified urine, after filtering off any BaSO₄ thrown down in the cold, is ever increasing.

[205] Pflüger’s Archiv, 13, 1876, 289.

Thus, a dog voided urine which contained in 100 c.c., ·262 grm. of precipitable sulphuric acid, and ·006 of organically-combined sulphuric acid; his back was now painted with carbolic acid, and the normal proportions were reversed, the precipitable sulphuric acid became ·004 grm., while the organically-combined was ·190 in 100 c.c. In addition to phenyl-sulphuric acid, it is now sufficiently established[206] that hydroquinone

( OH) (C₆H₄ ) ( OH)

(paradihydroxyl phenol) and pyrocatechin

( OH) (C₆H₄ ) ( OH)

(orthodihydroxyl phenol) are constant products of a portion of the phenol. The hydroquinone appears in the urine, in the first place, as the corresponding ether-sulphuric acid, which is colourless; but a portion of it is set free, and this free hydroquinone (especially in alkaline urine) is quickly oxidised to a brownish product, and hence the peculiar colour of urine. Out of dark coloured carbolic acid urine the hydroquinone and its products of decomposition can be obtained by shaking with ether; on separation of the ether, an extract is obtained, reducing alkaline silver solution, and developing quinone on warming with ferric chloride.

[206] E. Baumann and C. Preuss, Zeitschrift f. phys. Chemie, iii. 156; Anleitung zur Harn-Analyse, W. F. Löbisch, Leipzig, 1881, pp. 142, 160; Schmiedeberg, Chem. Centrbl. (3), 13, 598.

To separate pyro-catechin, 200 c.c. of urine may be evaporated to an extract, the extract treated with strong alcohol, the alcoholic liquid evaporated, and the extract then treated with ether. On separation and evaporation of the ether, a yellowish mass is left, from which the pyro-catechin may be extracted by washing with a small quantity of water. This solution will reduce silver solution in the cold, or, if treated with a few drops of ferric chloride solution, show a marked green colour, changing on being alkalised by a solution of sodic hydro-carbonate to violet, and then on being acidified by acetic acid, changing back again to green. According to Thudichum,[207] the urine of men and dogs, after the ingestion of carbolic acid, contains a blue pigment.

[207] On the Pathology of the Urine, Lond., 1877, p. 198.

§ 227. =The Action of Carbolic Acid considered physiologically.=--Researches on animals have elucidated, in a great measure, the mode in which carbolic acid acts, and the general sequence of effects, but there is still much to be learnt.

E. Küster[208] has shown that the temperature of dogs, when doses of carbolic acid in solution are injected subcutaneously, or into the veins, is immediately, or very soon after the operation, raised. With small and moderate doses, this effect is but slight--from half to a whole degree--on the day after the injection the temperature sinks below the normal point, and only slowly becomes again natural. With doses that are just lethal, first a rise and then a rapid sinking of temperature are observed; but with those excessive doses which speedily kill, the temperature at once sinks without a preliminary rise. The action on the heart is not very marked, but there is always a slowing of the cardiac pulsations; according to Hoppe-Seyler the arteries are relaxed. The respiration is much quickened; this acceleration is due to an excitement of the vagus centre, since Salkowsky has shown that section of the vagus produces a retardation of the respiratory wave. Direct application of the acid to muscles or nerves quickly destroys their excitability without a previous stage of excitement. The main cause of the lethal action of carbolic acid--putting on one side those cases in which it may kill by its local corrosive action--appears to be paralysis of the respiratory nervous centres. The convulsions arise from the spinal cord. On the cessation of the convulsions, the superficial nature of the breathing assists other changes by preventing the due oxidation of the blood.

[208] Archiv f. klin. Chirurgie, Bd. 23, S. 133, 1879.

§ 228. Carbolic acid is separated from the body in the forms already mentioned, a small portion is also excreted by the skin. Salkowsky considers that, with rabbits, he has also found oxalic acid in the urine as an oxidation product. According to the researches of Binnendijk,[209] the separation of carbolic acid by the urine commences very quickly after its ingestion; and, under favourable circumstances, it may be completely excreted within from twelve to sixteen hours. It must be remembered that normally a small amount of phenol may be present in the animal body, as the result of the digestion of albuminous substances or of their putrefaction. The amount excreted by healthy men when feeding on mixed diet, Engel,[210] by experiment, estimates to be in the twenty-four hours 15 mgrms.

[209] Journal de Pharmacie et de Chimie.

[210] Annal. de Chimie et de Physique, 5 Sér. T. 20, p. 230, 1880.

§ 229. =Post-mortem Appearances.=--No fact is better ascertained from experiments on animals than the following:--That with lethal doses of carbolic acid, administered by subcutaneous injection, or introduced by the veins, no appearances may be found after death which can be called at all characteristic. Further, in the cases in which death has occurred from the outward application of the acid for the cure of scabies, &c., no lesion was ascertained after death which could--apart from the history of the case and chemical evidence--with any confidence be ascribed to a poison.

On the other hand, when somewhat large doses of the acid are taken by the mouth, very coarse and appreciable changes are produced in the upper portion of the alimentary tract. There may be brownish, wrinkled spots on the cheek or lips; the mucous membrane of the mouth, throat, and gullet is often white, and if the acid was concentrated, eroded. The stomach is sometimes thickened, contracted, and blanched, a condition well shown in a pathological preparation (ix. 206, 43 f) in St. George’s Hospital. The mucous membrane, indeed, may be quite as much destroyed as if a mineral acid had been taken. Thus, in Guy’s Hospital museum (1799⁴⁰), there is preserved the stomach of a child who died from taking accidentally carbolic acid. It looks like a piece of paper, and is very white, with fawn-coloured spots; the rugæ are absent, and the mucous membrane seems to have entirely vanished. Not unfrequently the stomach exhibits white spots with roundish edges. The duodenum is often affected, and the action is not always limited to the first part of the intestine.

The respiratory passages are often inflamed, and the lungs infiltrated and congested. As death takes place from an asphyxiated condition, the veins of the head and brain, and the blood-vessels of the liver, kidney and spleen, are gorged with blood, and the right side of the heart distended, while the left is empty. On the other hand, a person may die of sudden nervous shock from the ingestion of a large quantity of the acid, and in such a case the post-mortem appearances will not then exhibit precisely the characters just detailed. Putrefaction is retarded according to the dose, and there is often a smell of carbolic acid.[211] If any urine is contained in the bladder, it will probably be dark, and present the characters of carbolic urine, detailed at p. 174.

[211] In order to detect this odour, it is well to open the head first, lest the putrefaction of the internal viscera be so great as to mask the odour.

Tests for Carbolic Acid.

§ 230. 1. =The Pinewood Test.=--Certain pinewood gives a beautiful blue colour when moistened first with carbolic acid, and afterwards with hydrochloric acid, and exposed to the light. Some species of pine give a blue colour with hydrochloric acid alone, and such must not be used; others do not respond to the test for carbolic acid. Hence it is necessary to try the chips of wood first, to see how they act, and with this precaution the test is very serviceable, and, in cautious hands, no error will be made.

2. =Ammonia and Hypochlorite Test.=--If to a solution containing even so small a quantity as 1 part of carbolic acid in 5000 parts of water, first, about a quarter of its volume of ammonia hydrate be added, and then a small quantity of sodic hypochlorite solution, avoiding excess, a blue colour appears, warming quickens the reaction: the blue is permanent, but turns to red with acids. If there is a smaller quantity than the above proportion of acid, the reaction may be still produced feebly after standing for some time.

3. =Ferric Chloride.=--One part of phenol in 3000 parts of water can be detected by adding a solution of ferric chloride; a fine violet colour is produced. This is also a very good test, when applied to a distillate; but if applied to a complex liquid, the disturbing action of neutral salts and other substances may be too great to make the reaction under those circumstances of service.

4. =Bromine.=--The most satisfactory test of all is treatment of the liquid by bromine-water. A precipitate of tri-bromo-phenol (C₆H₃Br₃O) is rapidly or slowly formed, according to the strength of the solution; in detecting very minute quantities the precipitate must be given time to form. According to Allen,[212] a solution containing but 1/60000 of carbolic acid gave the reaction after standing twenty-four hours.

[212] Commercial Organic Analysis, vol. i. p. 306.

The properties of the precipitate are as follows:--It is crystalline, and under the microscope is seen to consist of fine stars of needles; its smell is peculiar; it is insoluble in water and acid liquids, but soluble in alkalies, ether, and absolute alcohol; a very minute quantity of water suffices to precipitate it from an alcoholic solution; it is therefore essential to the success of the test that the watery liquid to be examined is either neutral or acid in reaction.

§ 231. Tri-bromo-phenol may be used for the quantitative estimation of carbolic acid, 100 parts of tri-bromo-phenol are equal to 29·8 of carbolic acid; by the action of sodium amalgam, tri-bromo-phenol is changed back into carbolic acid.

That bromine-water precipitates several volatile and fixed alkaloids from their solutions is no objection to the bromine test, for it may be applied to a distillation product, the bases having been previously fixed by sulphuric acid. Besides, the properties of tri-bromo-phenol are distinct enough, and therefore there is no valid objection to the test. It is the best hitherto discovered. There are also other reactions, such as that Millon’s reagent strikes a red--molybdic acid, in concentrated sulphuric acid, a blue--and potassic dichromate, with sulphuric acid, a brown colour--but to these there are objections. Again, we have the Euchlorine test, in which the procedure is as follows:--A test-tube is taken, and concentrated hydrochloric acid is allowed to act therein upon potassic chlorate. After the gas has been evolved for from 30 to 40 seconds, the liquid is diluted with 1½ volume of water, the gas removed by blowing through a tube, and solution of strong ammonia poured in so as to form a layer on the top; after blowing out the white fumes of ammonium chloride, a few drops of the sample to be tested are added. In the presence of carbolic acid, a rose-red, blood-red, or red-brown tint is produced, according to the quantity present. Carbolic acid may be confounded with cresol or with creasote, but the distinction between pure carbolic acid, pure cresol, and creasote is plain.

§ 232. =Cresol (Cresylic Acid, Methyl-phenol)=,

OH / C₆H₄ . \ CH₃

--There are three cresols--ortho-, meta-, and para-. Ordinary commercial cresol is a mixture of the three, but contains but little ortho-cresol; the more important properties of the pure cresols are set out in the following table:--

+--------+-----------------+----------------+---------------------+ | | Melting-point. | Boiling-point. | Converted by fusion | | | | | with Potash into-- | +--------+-----------------+----------------+---------------------+ |Ortho-, | 31-31·5° C. | 188·0° | Salicylic Acid | | | | | (Ortho-oxybenzoic | | | | | acid). | | | | | | |Meta-, |Fluid at ordinary| 201·0° | Meta-oxybenzoic | | | temperature. | | acid. | | | | | | |Para-, | 36° | 198° |Para-oxybenzoic acid.| +--------+-----------------+----------------+---------------------+

Pure ortho-, meta-, or para-cresol have been obtained by synthetical methods; they cannot be said to be in ordinary commerce.

=Commercial cresol= is at ordinary temperatures a liquid, and cannot be obtained in a crystalline state by freezing. Its boiling-point is from 198° to 203°; it is almost insoluble in strong ammonia, and, when 16 volumes are added, it then forms crystalline scales. On the other hand, carbolic acid is soluble in an equal volume of ammonia, and is then precipitated by the addition of 1½ volume of water. Cresol is insoluble in small quantities of pure 6 per cent. soda solution; with a large excess, it forms crystalline scales; while carbolic acid is freely soluble in small or large quantities of alkaline solutions.

Cold petroleum spirit dissolves cresol, but no crystalline scales can be separated out by a freezing mixture. Carbolic acid, on the contrary, is but sparingly soluble in cold petroleum, and a solution of carbolic acid in hot petroleum, when exposed to sudden cold produced by a freezing mixture, separates out crystals from the upper layer of liquid. Cresol is miscible with glycerin of specific gravity 1·258 in all proportions; 1 measure of glycerin mixed with 1 measure of cresol is completely precipitated by 1 measure of water. Carbolic acid, under the same circumstances, is not precipitated. The density of cresol is about 1·044. It forms with bromine a tri-bromo-cresol, but this is liquid at ordinary temperatures, while tri-bromo-phenol is solid. On the other hand, it resembles carbolic acid in its reactions with ferric chloride and with nitric and sulphuric acid.

§ 233. =Creasote= or =Kreozote= is a term applied to the mixture of crude phenols obtained from the distillation of wood-tar. It consists of a mixture of substances of which the chief are guaiacol or oxycresol (C₇H₈O₂), boiling at 200°, and creasol (C₈H₁₀O₂), boiling at 217°; also in small quantities phlorol (C₈H₁₀O), methyl creasol (C₉H₁₂O₂), and other bodies. Morson’s English creasote is prepared from Stockholm tar, and boils at about 217°, consisting chiefly of creasol; it is not easy, by mere chemical tests, to distinguish creasote from cresylic acid. Creasote, in its reactions with sulphuric and nitric acid, bromine and gelatin, is similar to carbolic and cresylic acids, and its solubility in most solvents is also similar. It is, however, distinguished from the tar acids by its insolubility in Price’s glycerin, specific gravity 1·258, whether 1, 2, or 3 volumes of glycerin be employed. But the best test is its action on an ethereal solution of nitro-cellulose. Creasote mixes freely with the B.P. collodium, while cresylic acid or carbolic acid at once coagulates the latter. With complicated mixtures containing carbolic acid, cresol, and creasote, the only method of applying these tests with advantage is to submit the mixture to fractional distillation.

Flückiger[213] tests for small quantities of carbolic acid in creasote, by mixing a watery solution of the sample with one-fourth of its volume of ammonia hydrate, wetting the inside of a porcelain dish with this solution, and then carefully blowing bromine fumes on to the surface. A fine blue colour appears if carbolic acid is present, but if the sample consists of creasote only, then it is dirty green or brown. Excess of bromine spoils the reaction.[214]

[213] Arch. der Pharmacie, cxiii. p. 30.

[214] Creasote is, without doubt, poisonous, though but little is known of its action, and very few experiments are on record in which pure creasote has been employed. Eulenberg has studied the symptoms in rabbits, by submitting them to vaporised creasote--i.e., the vapour from 20 drops of creasote diffused through a glass shade under which a rabbit was confined. There was at once great uneasiness, with a watery discharge from the eyes, and after seven minutes the rabbit fell on its side, and was slightly convulsed. The cornea was troubled, and the eyes prominent; a white slime flowed from the mouth and eyes. After fifteen minutes there was narcosis, with lessened reflex action; the temperature was almost normal. There was rattling breathing, and in half an hour the animal died, the respiration ceasing, and fluid blood escaping from the nose. Section after death showed the brain to be hyperæmic, the mucous membranes of the air-passages to be covered with a thin layer of fluid blood, and the lungs to be congested; the right side of the heart was gorged with fluid blood.

The post-mortem appearances and the symptoms generally are, therefore, closely allied to those produced by carbolic acid. A dark colour of the urine has also been noticed.

§ 234. =Carbolic Acid in Organic Fluids or in the Tissues of the Body.=--If the routine process given at page 51, where the organic fluid is distilled in a vacuum after acidifying with tartaric acid, is employed, phenol or cresol, if present, will certainly be found in the distillate. If, however, a special search be made for the acids, then the fluid must be well acidified with sulphuric acid, and distilled in the usual way. The distillation should be continued as long as possible, and the distillate shaken up with ether in the apparatus figured at page 156. On separation and evaporation of the ether, the tar acids, if present, will be left in a pure enough form to show its reactions. The same process applies to the tissues, which, in a finely-divided state, are boiled and distilled with dilute sulphuric acid, and the distillate treated as just detailed.

Like most poisons, carbolic acid has a selective attraction for certain organs, so that, unless all the organs are examined, it is by no means indifferent which particular portion is selected for the inquiry. Hoppe-Seyler applied carbolic acid to the abdomen and thighs of dogs, and when the symptoms were at their height bled them to death, and separately examined the parts. In one case, the blood yielded ·00369 per cent.; the brain, ·0034 per cent.; the liver, ·00125; and the kidneys, ·00423 per cent. of their weight of carbolic acid. The liver then contains only one-third of the quantity found in an equal weight of blood, and, therefore, the acid has no selective affinity for that organ. On the other hand, the nervous tissue, and especially the kidneys, appear to concentrate it.

§ 235. =Examination of the Urine for Phenol or Cresol.=--It has been previously stated (see p. 174) that the urine will not contain these as such, but as compounds--viz., phenyl or cresyl sulphate of potassium. By boiling with a mineral acid, these compounds may be broken up, and the acids obtained, either by distillation or by extraction with ether. To detect very minute quantities, a large quantity of the urine should be evaporated down to a syrup, and treated with hydrochloric acid and ether. On evaporating off the ether, the residue should be distilled with dilute sulphuric acid, and this distillate then tested with bromine-water, and the tri-bromo-phenol or cresol collected, identified, and weighed.

Thudichum[215] has separated crystals of potassic phenyl-sulphate itself from the urine of patients treated endermically by carbolic acid, as follows:--

[215] Pathology of the Urine, p. 193.

The urine was evaporated to a syrup, extracted with alcohol of 90 per cent., treated with an alcoholic solution of oxalic acid as long as this produced a precipitate, and then shaken with an equal volume of ether. The mixture was next filtered, neutralised with potassic carbonate, evaporated to a small bulk, and again taken up with alcohol. Some oxalate and carbonate of potassium were separated, and, on evaporation to a syrup, crystals of potassic phenyl-sulphate were obtained. They gave to analysis 46·25 per cent. H₂SO₄, and 18·1 K--theory requiring 46·2 of H₂SO₄ and 18·4 of K. Alkaline phenyl-sulphates strike a deep purple colour with ferric chloride. To estimate the amount of phenyl-sulphate or cresol-sulphate in the urine, the normal sulphates may be separated by the addition of chloride of barium in the cold, first acidifying with hydrochloric acid. On boiling the liquid a second crop of sulphate is obtained, due to the breaking up of the compound sulphate, and from this second weight the amount of acid can be obtained, e.g., in the case of phenol--C₆H₅HSO₄ : BaSO₄ :: 174 : 233.

§ 236. =Assay of Disinfectants, Carbolic Acid Powders, &c.=--For the assay of crude carbolic acid, Mr. Charles Lowe[216] uses the following process:--A thousand parts of the sample are distilled without any special condensing arrangement; water first comes over, and is then followed by an oily fluid. When a hundred parts of the latter, as measured in a graduated tube, have been collected, the receiver is changed. The volume of water is read off. If the oily liquid floats on the water, it contains light oil of tar; if it is heavier than the water, it is regarded as hydrated acid, containing 50 per cent. of real carbolic acid. The next portion consists of anhydrous cresylic and carbolic acids, and 625 volumes are distilled over; the remainder in the retort consists wholly of cresylic acid and the higher homologues. The relative proportions of carbolic and cresylic acids are approximately determined by taking the solidifying point, which should be between 15·5° and 24°, and having ascertained this temperature, imitating it by making mixtures of known proportions of carbolic and cresylic acids.

[216] Allen’s Commercial Organic Analysis, vol. i. p. 311.

E. Waller[217] has recommended the following process for the estimation of carbolic acid. It is based on the precipitation of the tar acids by bromine, and, of course, all phenols precipitated in this way will be returned as carbolic acid. The solutions necessary are--

[217] Chem. News, April 1, 1881, p. 152.

1. A solution containing 10 grms. of pure carbolic acid to the litre; this serves as a standard solution.

2. A solution of bromine in water.

3. Solution of alum in dilute sulphuric acid. A litre of 10 per cent. sulphuric acid is shaken with alum crystals until saturated.

The actual process is as follows:--10 grms. of the sample are weighed out and run into a litre flask, water added, and the mixture shaken. The flask being finally filled up to the neck, some of the solution is now filtered through a dry filter, and 10 c.c. of this filtrate is placed in a 6 or 8-ounce stoppered bottle, and 30 c.c. of the alum solution added. In a similar bottle 10 c.c. of the standard solution of carbolic acid are placed, and a similar quantity of alum solution is added, as in the first bottle. The bromine-water is now run into the bottle containing the standard solution of carbolic acid from a burette until there is no further precipitate; the bottle is stoppered and shaken after every addition. Towards the end of the reaction the precipitate forms but slowly, and when the carbolic acid is saturated, the slight excess of bromine-water gives the solution a pale yellow tint. The solution from the sample is treated in the same way, and from the amount of bromine-water used, the percentage of the sample is obtained by making the usual calculations. Thus, supposing that 5 c.c. of the standard required 15 c.c. of the bromine-water for precipitation, and 10 c.c. of the solution of the sample required 17 c.c., the calculation would be 15 × 2 : 17 = 100 : x per cent. With most samples of crude carbolic acid, the precipitate does not readily separate. It is then best to add a little of the precipitate already obtained by testing the standard solution, which rapidly clears the liquid.

=Koppeschaar’s volumetric method= is more exact, but also more elaborate, than the one just described. Caustic normal soda is treated with bromine until permanently yellow, and the excess of bromine is then driven off by boiling. The liquid now contains 5NaBr + NaBrO₃, and on adding this to a solution containing carbolic acid, and a sufficient quantity of hydrochloric acid to combine with the sodium, the following reactions occur:--

(1.) 5NaBr + NaBrO₃ + 6HCl = 6NaCl + 6Br + 3H₂O;

and

(2.) C₆H₆O + 6Br = C₆H₃Br₃O + 3HBr.

Any excess of bromine liberated in the first reaction above that necessary for the second, will exist in the free state, and from the amount of bromine which remains free the quantity of carbolic acid can be calculated, always provided the strength of the bromine solution is first known. The volumetric part of the analysis, therefore, merely amounts to the determination of free bromine, which is best found by causing it to react on potassium iodide, and ascertaining the amount of free iodine by titration with a standard solution of sodium thiosulphate. In other words, titrate in this way the standard alkaline bromine solution, using as an indicator starch paste until the blue colour disappears. Another method of indicating the end of the reaction is by the use of strips of paper first soaked in starch solution, and dried, and then the same papers moistened with zinc iodide, and again dried; the least excess of bromine sets free iodine, and strikes a blue colour.

=Colorimetric Method of Estimation.=--A very simple and ever-ready way of approximately estimating minute quantities of the phenols consists in shaking up 10 grms. of the sample with water, allowing any tar or insoluble impurities to subside. Ten c.c. of the clear fluid are then taken, and half a c.c. of a 5 per cent. solution of ferric chloride added. The colour produced is imitated by a standard solution of carbolic acid, and a similar amount of the reagent, on the usual principles of colorimetric analysis.

§ 237. =Carbolic Acid Powders.=--Siliceous carbolic acid powders are placed in a retort and distilled. Towards the end the heat may be raised to approaching redness. The distillate separates into two portions--the one aqueous, the other consisting of the acids--and the volume may be read off, if the distillate be received in a graduated receiver. Carbolic acid powders, having lime as a basis, may be distilled in the same way, after first decomposing with sulphuric acid. The estimation of the neutral tar oils in the distillate is easily performed by shaking the distillate with caustic soda solution, which dissolves completely the tar acids. The volume of the oils may be directly read off if the receiver is a graduated tube. Allen[218] has suggested the addition of a known volume of petroleum to the distillate, which dissolves the tar oils, and easily separates, and thus the volume may be more accurately determined, a correction being of course made by subtracting the volume of petroleum first added.

[218] Op. cit., i. p. 310.

§ 238. =Carbolic Acid Soap.=--A convenient quantity of soap is carefully weighed, and dissolved in a solution of caustic soda by means of heat. A saturated solution of salt is next added, sufficient to precipitate entirely the soap, which is filtered off; the filtrate is acidified with hydrochloric acid, and bromine water added. The precipitated tribromo-phenol is first melted by heat, then allowed to cool, and the mass removed from the liquid, dried, and weighed.

X.--Nitro-Benzene.

§ 239.--Nitro-benzene is the product resulting from the action of strong nitric acid on benzene. Its chemical formula is C₆H₅NO₂. When pure, it is of a pale yellow colour, of a density of 1·186, and boils at from 205° to 210°. It may be obtained in prismatic crystals by exposure to a temperature of 3°. Its smell is exactly the same as that from the oil or essence of bitter almonds; and it is from this circumstance, under the name of “essence of mirbane,” much used in the preparation of perfumes and flavouring agents.

In commerce there are three kinds of nitro-benzene--the purest, with the characters given above; a heavier nitro-benzene, boiling at 210° to 220°; and a very heavy variety, boiling at 222° to 235° The last is specially used for the preparation of aniline, or aniline blue. Nitro-benzene has been used as an adulterant of bitter almond oil, but the detection is easy (see “Foods,” p. 551). Nitro-benzene was first discovered by Mitscherlich in 1834, and its poisonous properties were first pointed out by Casper[219] in 1859. Its technical use in perfumes, &c., dates from about 1848, and in the twenty-eight years intervening between that date and 1876, Jübell[220] has collected 42 cases of poisoning by this agent, 13 of which were fatal. One of these cases was suicidal, the rest accidental.

[219] Vierteljahrsschrift für ger. Med., 1859, Bd. xvi. p. 1.

[220] Die Vergiftungen mit Blausäure u. Nitro-benzol in forensischer Beziehung, Erlangen, 1876.

§ 240. =Effects of Poisoning by Nitro-benzene.=--Nitro-benzene is a very powerful poison, whether taken in the form of vapour or as a liquid. The action of the vapour on animals has been studied by Eulenberg[221] and others. One experiment will serve as an illustration. Fifteen grms. of nitro-benzene were evaporated on warm sand under a glass shade, into which a cat was introduced. There was immediately observed in the animal much salivation, and quickened and laboured breathing. After thirty minutes’ exposure, on removing the shade to repeat the dose of 15 grms., the cat for the moment escaped. On being put back there was again noticed the salivation and running at the eyes, with giddiness, and repeated rising and falling. The animal at last, about one hour and forty minutes after the first dose, succumbed with dyspnœa, and died with progressive paralysis of the respiration. The membranes of the brain were found gorged with blood, the lungs liver-coloured, the mucous membrane of the trachea--to the finest sub-divisions of the bronchia--reddened, inflamed, and clothed with a fine frothy mucus. The left side of the heart was filled with thick black blood. The bladder contained 8 grms. of clear urine, in which aniline was discovered. There was a notable smell of bitter almonds.

[221] Gewerbe Hygiene, S. 607, Berlin, 1876.

§ 241. The effects of the vapour on man are somewhat different in their details to those just described. In a remarkable case related by Dr. Letheby, a man, aged 42, had spilt some nitro-benzene over his clothes. He went about several hours breathing an atmosphere of nitro-benzene, he then became drowsy, his expression was stupid, and his gait unsteady, presenting all the appearances of intoxication. The stupor suddenly deepened into coma, and the man died; the fatal course being altogether about nine hours--viz., four hours before coma, and five hours of total insensibility.

An interesting case of poisoning by the vapour is recorded by Taylor.[222] A woman, aged 30, tasted a liquid used for flavouring pastry, which was afterwards chemically identified as pure nitro-benzene. She immediately spat it out, finding that it had an acrid taste, and probably did not swallow more than a drop. In replacing the bottle, however, she spilt about a tablespoonful, and allowed it to remain for some minutes; it was a small room, and the vapour rapidly pervaded it, and caused illness in herself as well as in a fellow-servant. She had a strange feeling of numbness in the tongue, and in three hours and a quarter after the accident was seen by a medical man; she then presented all the appearances of prussic acid poisoning. The eyes were bright and glassy, the features pale and ghastly, the lips and nails purple, as if stained with blackberries, the skin clammy, and the pulse feeble, but the mind was then clear. An emetic was administered, but she suddenly became unconscious; the emetic acted, and brought up a fluid with an odour of nitro-benzene. The stomach-pump was also used, but the liquid obtained had scarcely any odour of nitro-benzene. In about eleven hours consciousness returned, and in about seventeen hours she partially recovered, but complained of flashes of light and strange colours before her eyes. Recovery was not complete for weeks. In this case the small quantity swallowed would probably of itself have produced no symptoms, and the effects are to be mainly ascribed to the breathing of the vapour.

[222] Poisons, Third Edition, p. 665.

§ 242. The liquid, when swallowed, acts almost precisely in the same way as the vapour, and the symptoms resemble very much those produced by prussic acid. The great distinction between prussic acid and nitro-benzene poisoning is that, in the latter, there is an interval between the taking of the poison and its effects. This is, indeed, one of the strangest phenomena of nitro-benzene poisoning, for the person, after taking it, may appear perfectly well for periods varying from a quarter of an hour to two or three hours, or even longer, and then there may be most alarming symptoms, followed by rapid death. Poisoning by nitro-benzene satisfies the ideal of the dramatist, who requires, for the purposes of his plot, poisons not acting at once, but with an interval sufficiently prolonged to admit of lengthy rhapsodies and a complicated dénouement. On drinking the poison there is a burning taste in the mouth, shortly followed by a very striking blueness or purple appearance of the lips, tongue, skin, nails, and even the conjunctivæ. This curious colour of the skin has, in one or two instances, been witnessed an hour before any feeling of illness manifested itself; vomiting then comes on, the vomited matter smelling of nitro-benzene. The skin is cold, there is great depression, and the pulse is small and weak. The respiration is affected, the breathing being slow and irregular, the breath smelling strongly of the liquid, and the odour often persisting for days. A further stage is that of loss of consciousness, and this comes on with all the suddenness of a fit of apoplexy. The coma is also similar in appearance to apoplectic coma, but there have frequently been seen trismus and convulsions of the extremities. The pupils are dilated and do not react to light, and reflex sensibility is sometimes completely extinguished. Cases vary a little in their main features; in a few the blue skin and the deep sleep are the only symptoms noted. Death, for the most part, occurs after a period of from eight to twenty-four hours (occasionally as soon as four or five hours) after taking the poison.

From the following remarkable train of symptoms in a dog, it is probable, indeed, that nitro-benzene, taken by a human being, might produce death, after a rather prolonged period of time, by its secondary effects:--To a half-bred greyhound[223] were administered 15 grms. of nitro-benzene, when shortly after there were noticed much salivation, shivering, and muscular twitchings. The same dose was repeated at the end of five, of seven, and of eight hours respectively, so that the dog altogether took 60 grms., but with no other apparent symptom than the profuse salivation. On the following day, the dog voided a tapeworm; vomiting supervened; the heart’s action was quickened, and the breathing difficult; convulsions followed, and the pupils were seen to be dilated. For eight days the dog suffered from dyspnœa, quickened pulse, shivering of the legs or of the whole body, tetanic spasms, bloody motions, great thirst and debility. The temperature gradually sank under 25°, and the animal finally died. The autopsy showed, as the most striking change, the whole mucous membrane of the intestinal tract covered with a yellow layer, which chemical analysis proved to be caused by picric acid, and in the urine, liver, and lungs, aniline was discovered.

[223] Eulenberg, Gewerbe Hygiene, S. 607.

§ 243. =Fatal Dose.=--It is probable, from recorded cases, that 1 grm. (15·4 grains) would be quite sufficient to kill an adult, and, under favourable circumstances, less than that quantity. It would seem that spirituous liquids especially hasten and intensify the action of nitro-benzene, so that a drunken person, cæteris paribus, taking the poison with spirits, would be more affected than taking it under other conditions.

In a case related by Stevenson,[224] in which so small a quantity as 1·74 grm. was taken in seven doses, spread over more than forty-eight hours; there were yet extremely alarming symptoms, and the patient seems to have had a narrow escape. On the other hand, a woman admitted into the General Hospital, Vienna, took 100 grms. (about 3½ ozs.) and recovered; on admission she was in a highly cyanotic condition, with small pulse, superficial respiration, and dribbling of urine, which contained nitro-benzol. Artificial respiration was practised, and camphor injections were administered. Under this treatment consciousness was restored, and the patient recovered. On the fourth day the urine resembled that of a case of cystitis (Lancet, Jan. 16, 1894). The quantity of nitro-benzene which would be fatal, if breathed, is not known with any accuracy.

[224] This case is not uninteresting. Through a mistake in reading an extremely illegible prescription, M. S. S., æt. 21, was supplied by a druggist with the following mixture;--

℞. Benzole-Nit., ʒiij. Ol. Menth, pep., ʒss. Ol. Olivæ, ʒx. gutt. xxx., t. ds.

He took on sugar seven doses, each of 20 minims, equalling in all 23 min. (or by weight 27·1 grains, 1·74 grm.) of nitro-benzene--viz., three doses on the first day, three on the second, and one on the morning of the third day. The first two days he was observed to be looking pale and ill, but went on with his work until the seventh dose, which he took on the third day at 9 A.M. About 2 P.M. (or six hours after taking the seventh dose), he fell down insensible, the body pale blue, and with all the symptoms already described in the text, and usually seen in nitro-benzene poisoning. With suitable treatment he recovered. The next morning, from 8 ounces of urine some nitro-benzene was extracted by shaking with chloroform.--Thos. Stevenson, M.D., in Guy’s Hospital Reports, MS., vol. xxi., 1876.

§ 244. =Pathological Appearances.=--The more characteristic appearances seem to be, a dark brown or even black colour of the blood, which coagulates with difficulty (an appearance of the blood that has even been noticed during life), venous hyperæmia of the brain and its membranes, and general venous engorgement. In the stomach, when the fluid has been swallowed, the mucous membrane is sometimes reddened diffusely, and occasionally shows ecchymoses of a punctiform character.

§ 245. =The essential action of nitro-benzene= is of considerable physiological interest. The blood is certainly in some way changed, and gives the spectrum of acid hæmatin.[225] Filehne has found that the blood loses, in a great degree, the power of carrying and imparting oxygen to the tissues, and its content of carbon dioxide is also increased. Thus, the normal amount of oxygen gas which the arterial blood of a hound will give up is 17 per cent.; but in the case of a dog which had been poisoned with nitro-benzene, it sank to 1 per cent. During the dyspnœa from which the dog suffered, the carbon dioxide exhaled was greater than the normal amount, and the arterial blood (the natural content of which should have been 30 per cent. of this gas), only gave up 9 per cent. Filehne seeks to explain the peculiar colour of the skin by the condition of the blood, but the explanation is not altogether satisfactory. Some part of the nitro-benzene, without doubt, is reduced to aniline in the body--an assertion often made, and as often contradicted--but it has been found in too many cases to admit of question. It would also seem from the experiment on the dog (p. 186), that a conversion into picric acid is not impossible. A yellow colour of the skin and conjunctivæ, as if picric-acid-stained, has been noticed in men suffering under slow poisoning by nitro-benzene.

[225] Filehne, W., “Ueber die Gift-Wirkungen des Nitrobenzols,” Arch. für exper. Pathol. u. Pharm., ix. 329.

§ 246. =Detection and Separation of Nitro-Benzene from the Animal Tissues.=--It is evident from the changes which nitro-benzene may undergo that the expert, in any case of suspected nitro-benzene poisoning, must specially look (1) for nitro-benzene, (2) for aniline, and (3) for picric acid. The best general method for the separation of nitro-benzene is to shake up the liquid (or finely-divided solid) with light benzoline (petroleum ether), which readily dissolves nitro-benzene. On evaporation of the petroleum ether, the nitro-benzene is left, perhaps mixed with fatty matters. On treating with cold water, the fats rise to the surface, and the nitro-benzene sinks to the bottom; so that, by means of a separating funnel, the nitro-benzene may be easily removed from animal fats. The oily drops, or fine precipitate believed to be nitro-benzene, may be dissolved in spirit and reduced to aniline by the use of nascent hydrogen, developed from iron filings by hydrochloric acid, and the fluid tested with bleaching powder, or, the aniline itself may be recovered by alkalising the fluid, and shaking up with ether in the separation-tube (p. 156), the ether dissolves the aniline, and leaves it, on spontaneous evaporation, as an oily yellowish mass, which, on the addition of a few drops of sodic hypochlorite, strikes a blue or violet-blue--with acids, a rose-red--and with bromine, a flesh-red. It gives alkaloidal reactions with such general reagents as platinum chloride, picric acid, &c. Aniline itself may be extracted from the tissues and fluids of the body by petroleum ether, but in any special search it will be better to treat the organs as in Stas’ process--that is, with strong alcohol, acidified with sulphuric acid. After a suitable digestion in this menstruum, filter, and then, after evaporating the alcohol, dissolve the alcoholic extract in water; alkalise the aqueous solution, and extract the aniline by shaking it up with light benzoline. On separating the benzoline, the aniline will be left, and may be dissolved in feebly-acid water, and the tests before enumerated tried.

Malpurgo[226] recommends the following test for nitro-benzene:--2 drops of melted phenol, 3 drops of water, and a fragment of caustic potash are boiled in a small porcelain dish, and to the boiling liquid the aqueous solution to be tested is added. On prolonged boiling, if nitro-benzene is present, a crimson ring is produced at the edges of the liquid; this crimson colour, on the addition of a little bleaching powder, turns emerald-green.

[226] Zeit. anal. Chem., xxxii. 235.

Oil of bitter almonds may be distinguished from nitro-benzene by the action of manganese dioxide and sulphuric acid; bitter almond oil treated in this way loses its odour, nitro-benzene is unaltered. To apply the test, the liquid must be heated on the water-bath for a little time.

XI.--Dinitro-benzol.

§ 247. =Dinitro-benzol=, C₆H₄(NO₂)₂ (ortho-, meta-, para-).--The ortho-compound is produced by the action of nitric acid on benzol, aided by heat in the absence of strong sulphuric acid to fix water. Some of the para-dinitro-benzol is at the same time produced. The meta-compound is obtained by the action of fuming nitric acid on nitro-benzol at a boiling temperature.

The physical properties of the three dinitro-benzols are briefly as follows:--

Ortho-d. is in the form of needles; m.p. 118°.

Meta-d. crystallises in plates; m.p. 90°.

Para-d. crystallises, like the ortho-compound, in needles, but the melting-point is much higher, 171° to 172°.

Just as nitro-benzol by reduction yields aniline, so do the nitro-benzols on reduction yield ortho-, meta-, or para-phenylene diamines.

Meta-phenylene diamine is an excellent test for nitrites; and, since the commercial varieties of dinitro-benzol either consist mainly or in part of meta-dinitro-benzol, the toxicological detection is fairly simple, and is based upon the conversion of the dinitro-benzol into meta-phenylene-diamine.

Dinitro-benzol is at present largely employed in the manufacture of explosives, such as roburite, sicherheit, and others. It has produced much illness among the workpeople in the manufactures, and amongst miners whose duty it has been to handle such explosives.

§ 248. =Effects of Dinitro-benzol.=--Huber[227] finds that if dinitro-benzol is given to frogs by the mouth in doses of from 100 to 200 mgrms., death takes place in a few hours. Doses of from 2·5 to 5 mgrms. cause general dulness and ultimately complete paralysis, and death in from one to six days.

[227] “Beiträge zur Giftwirkung des Dinitrobenzols,” A. Huber, Virchow’s Archiv, 1891, Bd. 126, S. 240.

Rabbits are killed by doses of 400 mgrms., in time varying from twenty-two hours to four days.

In a single experiment on a small dog, the weight of which was 5525 grms., the dog died in six hours after a dose of 600 mgrms.

It is therefore probable that a dose of 100 mgrms. per kilo would kill most warm-blooded animals.

A transient exposure to dinitro-benzol vapours in man causes serious symptoms; for instance, in one of Huber’s cases, a student of chemistry had been engaged for one hour and a half only in preparing dinitro-benzol, and soon afterwards his comrades remarked that his face was of a deep blue colour. On admission to hospital, on the evening of the same day, he complained of slight headache and sleeplessness; both cheeks, the lips, the muscles of the ear, the mucous membrane of the lips and cheeks, and even the tongue, were all of a more or less intense blue-grey colour. The pulse was dicrotic, 124; T. 37·2°. The next morning the pulse was slower, and by the third day the patient had recovered.

Excellent accounts of the effects of dinitro-benzol in roburite factories have been published by Dr. Ross[228] and Professor White,[229] of Wigan. Mr. Simeon Snell[230] has also published some most interesting cases of illness, cases which have been as completely investigated as possible. As an example of the symptoms produced, one of Mr. Snell’s cases may be here quoted.

[228] Medical Chronicle, 1889, 89.

[229] Practitioner, 1889, ii. 15.

[230] Brit. Med. Journ., March 3, 1894.

C. F. W., aged 38, consulted Mr. Snell for his defective sight on April 9, 1892. He had been a mixer at a factory for the manufacture of explosives. He was jaundiced, the conjunctiva yellow, and the lips blue. He was short of breath, and after the day’s work experienced aching of the forearms and legs and tingling of the fingers. The urine was black in colour, of sp. gr. 1024; it was examined spectroscopically by Mr. MacMunn, who reported the black colour as due neither to indican, nor to blood, nor bile, but to be caused by some pigment belonging to the aromatic series. The patient’s sight had been failing since the previous Christmas. Vision in the right eye was 6/24, left 6/36, both optic papillæ were somewhat pale. In each eye there was a central scotoma for red, and contraction of the field (see diagram). The man gradually gave up the work, and ultimately seems to have recovered. It is, however, interesting to note that, after having left the work for some weeks, he went back for a single day to the “mixing,” and was taken very ill, being insensible and delirious for five hours.

§ 249. =The Blood in Nitro-benzol Poisoning.=--The effect on the blood has been specially studied by Huber.[231] The blood of rabbits poisoned by dinitro-benzol is of a dark chocolate colour, and the microscope shows destruction of the red corpuscles; the amount of destruction may be gathered from the following:--the blood corpuscles of a rabbit before the experiment numbered 5,588,000 per cubic centimetre; a day after the experiment 4,856,000; a day later 1,004,000; on the third day the rabbit died.

[231] Op. cit.

In one rabbit, although the corpuscles sank to 1,416,000, yet recovery took place.

Dr. MacMunn[232] has examined specimens of blood from two of Mr. Snell’s patients; he found a distinct departure from the normal; the red corpuscles were smaller than usual, about 5 or 6 µ in diameter, and the appearances were like those seen in pernicious anæmia. Huber, in some of his experiments on animals, found a spectroscopic change in the blood, viz., certain absorption bands, one in the red between C and D, and two in the green between D and E; the action of reducing agents on this dinitro-benzol blood, as viewed in a spectroscope provided with a scale in which C = 48, D = 62, and E = 80·5, was as follows:--

[232] Op. cit.

Dinitro-Bands. In Red. In Green. -----/\----- 50-52 62-66 70-77 After NH₄SO₄, 53-55 62-66 70-77 „ NH₃, 54-58 60-65 70-77 „ NH₄SO₄ + NH₃, 52-55 60-65 70-77

Taking the symptoms as a whole, there has been noted:--a blue colour of the lips, not unfrequently extending over the whole face, and even the conjunctivæ have been of a marked blue colour, giving the sufferer a strange livid appearance. In other cases there have been jaundice, the conjunctivæ and the skin generally being yellow, the lips blue. Occasionally gastric symptoms are present. Sleeplessness is common, and not unfrequently there is some want of muscular co-ordination, and the man staggers as if drunk. In more than one case there has been noticed sudden delirium. There is in chronic cases always more or less anæmia, and the urine is remarkable in its colour, which ranges from a slightly dark hue up to positive blackness. In a large proportion of cases there is ophthalmic trouble, the characteristics of which (according to Mr. Snell) are “failure of sight, often to a considerable degree, in a more or less equal extent on the two sides; concentric attraction of visual field with, in many cases, a central colour scotoma; enlargement of retinal vessels, especially the veins; some blurring, never extensive, of edges of disc, and a varying degree of pallor of its surface--the condition of retinal vessels spoken of being observed in workers with the dinitro-benzol, independently of complaints of defective sight. Cessation of work leads to recovery.”

§ 250. =Detection of Dinitro-benzol.=--Dinitro-benzol may be detected in urine, in blood, and in fluids generally, by the following process:--Place tinfoil in the fluid, and add hydrochloric acid to strong acidity, after allowing the hydrogen to be developed for at least an hour, make the fluid alkaline by caustic soda, and extract with ether in a separating tube; any metaphenylene-diamine will be contained in the ether; remove the ether into a flask, and distil it off; dissolve the residue in a little water.

Acidify a solution of sodium nitrite with dilute sulphuric acid; on adding the solution, if it contains metaphenylene-diamine, a yellow to red colour will be produced, from the formation of Bismarck brown (triamido-phenol).

XII.--Hydrocyanic Acid.

§ 251. =Hydrocyanic Acid= (=hydric cyanide=)--specific gravity of liquid 0·7058 at 18° C., boiling-point 26·5° (80° F.), HCy = 27.--The anhydrous acid is not an article of commerce, and is only met with in the laboratory. It is a colourless, transparent liquid, and so extremely volatile that, if a drop fall on a glass plate, a portion of it freezes. It has a very peculiar peach-blossom odour, and is intensely poisonous. It reddens litmus freely and transiently, dissolves red oxide of mercury freely, forms a white precipitate of argentic cyanide when treated with silver nitrate, and responds to the other tests described hereafter.

§ 252. =Medicinal Preparations of Prussic Acid.=--The B.P. acid is a watery solution of prussic acid; its specific gravity should be 0·997, and it should contain 2 per cent. of the anhydrous acid, 2 per cent. is also the amount specified in the pharmacopœias of Switzerland and Norway, and in that of Borussica (VI. ed.); the latter ordains, however, a spirituous solution, and the Norwegian an addition of 1 per cent. of concentrated sulphuric acid. The French prussic acid is ordered to be prepared of a strength equalling 10 per cent.

The adulterations or impurities of prussic acid are hydrochloric, sulphuric,[233] and formic acids. Traces of silver may be found in the French acid, which is prepared from cyanide of silver. Tartaric acid is also occasionally present. Hydrochloric acid is most readily detected by neutralising with ammonia, and evaporating to dryness in a water-bath; the ammonium cyanide decomposes and volatilises, leaving as a saline residue chloride of ammonium. This may easily be identified by the precipitate of chloride of silver, which its solution gives on testing with silver nitrate, and the deep brown precipitate with Nessler solution. Sulphuric acid is, of course, detected by chloride of barium; formic acid by boiling a small quantity with a little mercuric oxide; if present, the oxide will be reduced, and metallic mercury fall as a grey precipitate. Silver, tartaric acid, and any other fixed impurities are detected by evaporating the acid to dryness, and examining any residue which may be left. It may be well to give the various strengths of the acids of commerce in a tabular form:--

[233] A trace of sulphuric or hydrochloric acid should not be called an adulteration, for it greatly assists the preservation, and therefore makes the acid of greater therapeutic efficiency.

Per cent.

British Pharmacopœia, Switzerland, and Bor. (vj), 2 France, 10 Vauquelin’s Acid, 3·3 Scheele’s „ 4 to 5[234] Riner’s „ 10 Robiquet’s „ 50 Schraeder’s „ 1·5 Duflos’ „ 9 Pfaff’s „ 10 Koller’s „ 25

[234] Strength very uncertain.

In English commerce, the analyst will scarcely meet with any acid stronger than Scheele’s 5 per cent.

Impure oil of bitter almonds contains hydric cyanide in variable quantity, from 5 per cent. up to 14 per cent. There is an officinal preparation obtained by digesting cherry-laurel leaves in water, and then distilling a certain portion over. This Aqua Lauro-cerasi belongs to the old school of pharmacy, and is of uncertain strength, but varies from ·7 to 1 per cent. of HCN.

§ 253. =Poisoning by Prussic Acid.=--Irrespective of suicidal or criminal poisoning, accidents from prussic acid may occur--

1. From the use of the cyanides in the arts.

2. From the somewhat extensive distribution of the acid, or rather of prussic-acid producing substances in the vegetable kingdom.

1. =In the Arts.=--The galvanic silvering[235] and gilding of metals, photography, the colouring of black silks, the manufacture of Berlin blue, the dyeing of woollen cloth, and in a few other manufacturing processes, the alkaline cyanides are used, and not unfrequently fumes of prussic acid developed.

[235] The preparation used for the silvering of copper vessels is a solution of cyanide of silver in potassic cyanide, to which is added finely powdered chalk. Manipulations with this fluid easily develop hydrocyanic acid fumes, which, in one case related by Martin (Aerztl. Intelligenzbl., p. 135, 1872), were powerful enough to produce symptoms of poisoning.

2. =In the Animal Kingdom.=--One of the myriapods (Chilognathen) contains glands at the roots of the hairs, which secrete prussic acid; when the insect is seized, the poisonous secretion is poured out from the so-called foramina repugnatoria.

3. =In the Vegetable Kingdom.=--A few plants contain cyanides, and many contain amygdalin, or bodies formed on the type of amygdalin. In the presence of emulsin (or similar principles) and water, this breaks up into prussic acid and other compounds--an interesting reaction usually represented thus--

C₂₀H₂₇NO₁₁ + 2H₂O = CNH + C₇H₆O + 2C₆H₁₂O₆.

1 equivalent of amygdalin--i.e., 457 parts--yielding 1 equivalent of CNH or 27 parts; in other words, 100 parts of amygdalin yield theoretically 5·909 parts of prussic acid,[236] so that, the amount of either being known, the other can be calculated from it.

[236] According to Liebig and Wöhler, 17 grms. of amygdalin yield 1 of prussic acid (i.e., 5·7 per cent.) and 8 of oil of bitter almonds. Thirty-four parts of amygdalin, mixed with 66 of emulsin of almonds, give a fluid equalling the strength of acid of most pharmacopœias, viz., 2 per cent.

Greshoff[237] has discovered an amygdalin-like glucoside in the two tropical trees Pygeum parriflorum and P. latifolium. The same author states that the leaves of Gymnema latifolium, one of the Asclepiads, yields to distillation benzaldehyde hydrocyanide. Both Lasia and Cyrtosperma, plants belonging to the natural family of the Orontads, contain in their flowers potassic cyanide. Pangium edule, according to Greshoff, contains so much potassic cyanide that he was able to prepare a considerable quantity of that salt from one sample of the plant. An Indian plant (Hydnocarpus inebrians) also contains a cyanide, and has been used for the purpose of destroying fish. Among the Tiliads, Greshoff found that Echinocarpus Sigun yielded hydrocyanic acid on distillation. Even the common linseed contains a glucoside which breaks up into sugar, prussic acid, and a ketone.

[237] M. Greshoff--Erster Bericht über die Untersuchung von Pflanzenstoffen Niederländisch-Indiens. Mittheilungen aus dem chemisch-pharmakologischen Laboratorium des botan. Gartens des Staates, vii., Batavia, 1890, Niederländisch. Dr. Greshoff’s research indicates that there are several other cyanide-yielding plants than those mentioned in the text.

The following plants, with many others, all yield, by appropriate treatment, more or less prussic acid:--Bitter almonds (Amygdalus communis); the Amygdalus persica; the cherry laurel (Prunus laurocerasus); the kernels of the plum (Prunus domestica); the bark, leaves, flowers, and fruit of the wild service-tree (Prunus padus); the kernels of the common cherry and the apple; the leaves of the Prunus capricida; the bark of the Pr. virginiana; the flowers and kernels of the Pr. spinosa; the leaves of the Cerasus acida; the bark and almost all parts of the Sorbus aucuparia, S. hybrida, and S. torminalis; the young twigs of the Cratægus oxyacantha; the leaves and partly also the flowers of the shrubby Spiræaceæ, such as Spiræa aruncus, S. sorbifolia, and S. japonica;[238] together with the roots of the bitter and sweet Cassava.

[238] The bark and green parts of the Prunus avium, L., Prunus mahaleb, L., and herbaceous Spirææ yield no prussic acid.

In only a few of these, however, has the exact amount of either prussic acid or amygdalin been determined; 1 grm. of bitter almond pulp is about equal to 2½ mgrms. of anhydrous prussic acid. The kernels from the stones of the cherry, according to Geiseler, yield 3 per cent. of amygdalin; therefore, 1 grm. equals 1·7 mgrm. of HCN.

§ 254. The wild service-tree (Prunus padus) and the cherry-laurel (Prunus Laurocerasus) contain, not amygdalin but a compound of amygdalin with amygdalic acid; to this has been given the name of laurocerasin. It was formerly known as amorphous amygdalin; its formula is C₄₀H₅₅NO₂₄; 933 parts are equivalent to 27 of hydric cyanide--that is, 100 parts equal to 2·89.

In the bark of the service-tree, Lehmann found ·7 per cent. of laurocerasin (= ·02 HCN), and in the leaves of the cherry-laurel 1·38 per cent. (= 0·39 HCN).

Francis,[239] in a research on the prussic acid in cassava root, gives as the mean in the sweet cassava ·0168 per cent., in the bitter ·0275 per cent., the maximum in each being respectively ·0238 per cent., and ·0442 per cent. The bitter-fresh cassava root has long been known as a very dangerous poison; but the sweet has hitherto been considered harmless, although it is evident that it also contains a considerable quantity of prussic acid.

[239] “On Prussic Acid from Cassava,” Analyst, April 1877, p. 5.

The kernels of the peach contain about 2·85 per cent. amygdalin (= ·17 HCN); those of the plum ·96 per cent. (= ·056 HCN); and apple pips ·6 per cent. (= ·035 per cent. HCN).

It is of great practical value to know, even approximately, the quantity of prussic acid contained in various fruits, since it has been adopted as a defence in criminal cases that the deceased was poisoned by prussic acid developed in substances eaten.

§ 255. =Statistics.=--Poisoning by the cyanides (prussic acid or cyanide of potassium) occupies the third place among poisons in order of frequency in this country, and accounts for about 40 deaths annually.

In the ten years ending 1892 there were recorded no less than 395 cases of accidental, suicidal, or homicidal poisoning by prussic acid and potassic cyanide. The further statistical details may be gathered from the following tables:--

DEATHS IN ENGLAND AND WALES DURING THE TEN YEARS 1883-1892 FROM PRUSSIC ACID AND POTASSIC CYANIDE.

PRUSSIC ACID (ACCIDENT OR NEGLIGENCE).

Ages, 0-1 1-5 5-15 15-25 25-65 65 and Total above Males, ... 1 1 1 12 1 16 Females, 1 1 ... 2 7 ... 11 -------------------------------------------- Totals, 1 2 1 3 19 1 27 --------------------------------------------

CYANIDE OF POTASSIUM (ACCIDENT OR NEGLIGENCE).

Ages, 1-5 5-15 15-25 25-65 65 and Total above Males, 1 1 4 1 ... 7 Females, 1 ... ... 3 ... 4 --------------------------------------- Totals, 2 1 4 4 ... 11 ---------------------------------------

PRUSSIC ACID (SUICIDE).

Ages, 15-25 25-65 65 and Total above Males, 23 156 23 202 Females, 5 13 1 19 ---------------------------- Totals, 28 169 24 221 ----------------------------

POTASSIUM CYANIDE (SUICIDE).

Ages, 5-15 15-25 25-65 65 and Total above Males, 1 6 88 5 100 Females, ... 6 15 1 22 ---------------------------------- Totals, 1 12 103 6 122 ----------------------------------

To these figures must be added 10 cases of murder (2 males and 8 females) by prussic acid, and 4 cases of murder (3 males and 1 female) by potassic cyanide.

In order to ascertain the proportion in which the various forms of commercial cyanides cause death, and also the proportion of accidental, suicidal, and criminal deaths from the same cause, Falck collated twelve years of statistics from medical literature with the following result:--

In 51 cases of cyanide poisoning, 29 were caused by potassic cyanide, 9 by hydric cyanide, 5 by oil of bitter almonds, 3 by peach stones (these 3 were children, and are classed as “domestic,” that is, taking the kernels as a food), 3 by bitter almonds (1 of the 3 suicidal and followed by death, the other 2 “domestic”), 1 by tartaric acid and potassic cyanide (a suicidal case, an apothecary), and 1 by ferro-cyanide of potassium and tartaric acid. Of the 43 cases first mentioned, 21 were suicidal, 7 criminal, 8 domestic, and 7 medicinal; the 43 patients were 24 men, 14 children, and 5 women.

The cyanides are very rarely used for the purpose of murder: a poison which has a strong smell and a perceptible taste, and which also kills with a rapidity only equalled by deadly bullet or knife-wounds, betrays its presence with too many circumstances of a tragic character to find favour in the dark and secret schemes of those who desire to take life by poison. In 793 poisoning cases of a criminal character in France, 4 only were by the cyanides.

Hydric and potassic cyanides were once the favourite means of self-destruction employed by suicidal photographers, chemists, scientific medical men, and others in positions where such means are always at hand; but, of late years, the popular knowledge of poisons has increased, and self-poisoning by the cyanides scarcely belongs to a particular class. A fair proportion of the deaths are also due to accident or unfortunate mistakes, and a still smaller number to the immoderate or improper use of cyanide-containing vegetable products.

§ 256. =Accidental and Criminal Poisoning by Prussic Acid.=--The poison is almost always taken by the mouth into the stomach, but occasionally in other ways--such, for example, as in the case of the illustrious chemist, Scheele, who died from inhalation of the vapour of the acid which he himself discovered, owing to the breaking of a flask. There is also the case related by Tardieu, in which cyanide of potassium was introduced under the nails; and that mentioned by Carrière,[240] in which a woman gave herself, with suicidal intent, an enema containing cyanide of potassium. It has been shown by experiments, in which every care was taken to render it impossible for the fumes to be inhaled, that hydrocyanic acid applied to the eye of warm-blooded animals may destroy life in a few minutes.[241]

[240] “Empoisonnement par le cyanure de potassium,--guérison,” Bullet. général de Thérap., 1869, No. 30.

[241] N. Gréhant, Compt. rend. Soc. Biol. [9], xi. 64, 65.

With regard to errors in dispensing, the most tragic case on record is that related by Arnold:[242]--A pharmaceutist had put in a mixture for a child potassic cyanide instead of potassic chlorate, and the child died after the first dose: the chemist, however, convinced that he had made no mistake, to show the harmlessness of the preparation, drank some of it, and there and then died; while Dr. Arnold himself, incautiously tasting the draught, fell insensible, and was unconscious for six hours.

[242] Arnold, A. B., “Case of Poisoning by the Cyanide of Potassium,” Amer. Journ. of Med. Scien., 1869.

§ 257. =Fatal Dose.=--Notwithstanding the great number of persons who in every civilised country fall victims to the cyanides, it is yet somewhat doubtful what is the minimum dose likely to kill an adult healthy man. The explanation of this uncertainty is to be sought mainly in the varying strength of commercial prussic acid, which varies from 1·5 (Schraeder’s) to 50 per cent. (Robiquet’s), and also in the varying condition of the person taking the poison, more especially whether the stomach be full or empty. In by far the greater number, the dose taken has been much beyond that necessary to produce death, but this observation is true of most poisonings.

The dictum of Taylor, that a quantity of commercial prussic acid, equivalent to 1 English grain (65 mgrm.) of the anhydrous acid, would, under ordinary circumstances, be sufficient to destroy adult life, has been generally accepted by all toxicologists. The minimum lethal dose of potassic cyanide is similarly put at 2·41 grains (·157 grm.). As to bitter almonds, if it be considered that as a mean they contain 2·5 per cent. of amygdalin, then it would take 45 grms., or about 80 almonds, to produce a lethal dose for an adult; with children less--in fact, 4 to 6 bitter almonds are said to have produced poisoning in a child.

§ 258. =Action of Hydric and Potassic Cyanides on Living Organisms.=--Both hydric cyanide and potassic cyanide are poisonous to all living forms, vegetable or animal, with the exception of certain fungi. The cold-blooded animals take a larger relative dose than the warm-blooded, and the mammalia are somewhat more sensitive to the poisonous action of the cyanides than birds; but all are destroyed in a very similar manner, and without any essential difference of action. The symptoms produced by hydric and potassic cyanide are identical, and, as regards general symptoms, what is true as to the one is also true as to the other. There is, however, one important difference in the action of these two substances, if the mere local action is considered, for potassic cyanide is very alkaline, possessing even caustic properties. I have seen, e.g., the gastric mucous membrane of a woman, who had taken an excessive dose of potassic cyanide on an empty stomach, so inflamed and swollen, that its state was similar to that induced by a moderate quantity of solution of potash. On the other hand, the acid properties of hydric cyanide are very feeble, and its effect on mucous membranes or the skin in no way resembles that of the mineral acids.

It attacks the animal system in two ways: the one, a profound interference with the ordinary metabolic changes; the other, a paralysis of the nervous centres. Schönbein discovered that it affected the blood corpuscles in a peculiar way; normal blood decomposes with great ease hydrogen peroxide into oxygen and water. If to normal venous blood a little peroxide of hydrogen be added, the blood at once becomes bright red; but if a trace of prussic acid be present, it is of a dark brown colour. The blood corpuscles, therefore, lose their power of conveying oxygen to all parts of the system, and the phenomena of asphyxia are produced. Geppert[243] has proved that this is really the case by showing, in a series of researches, that, under the action of hydric cyanide, less oxygen is taken up, and less carbon dioxide formed than normal, even if the percentage of oxygen in the atmosphere breathed is artificially increased. The deficiency of oxygen is in part due to the fact that substances like lactic acid, the products of incomplete combustion, are formed instead of CO₂.

[243] Geppert, Ueber das Wesen der CNH-Vergift; mit einer Tafel, Berlin, 1889; Sep.-Abdr. aus Ztschr. f. klin. Med., Bd. xv.

At the same time the protoplasm of the tissues is paralysed, and unable to take up the loosely bound oxygen presented. This explains a striking symptom which has been noticed by many observers, that is, if hydrocyanic acid be injected into an animal, the venous blood becomes of a bright red colour; in warm-blooded animals this bright colour is transitory, but in cold-blooded animals, in which the oxidation process is slower, the blood remains bright red.

§ 259. =Symptoms observed in Animals.=--The main differences between the symptoms induced in cold-blooded and warm-blooded animals, by a fatal dose of hydric cyanide, are as follows:--

The respiration in frogs is at first somewhat dyspnœic, then much slowed, and at length it ceases. The heart, at first slowed, later contracts irregularly, and at length gradually stops; but it may continue to beat for several minutes after the respiration has ceased. But all these progressive symptoms are without convulsion. Among warm-blooded animals, on the contrary, convulsions are constant, and the sequence of the symptoms appears to be--dyspnœa, slowing of the pulse, giddiness, falling down, then convulsions with expulsion of the urine and fæces; dilatation of the pupils, exophthalmus, and finally cessation of the pulse and breathing. The convulsions also frequently pass into general paralysis, with loss of reflex movements, weak, infrequent breathing, irregular, quick, and very frequent pulse, and considerable diminution of temperature.

The commencement of the symptoms in animals is extremely rapid, the rapidity varying according to the dose and the concentration of the acid. It was formerly thought that the death from a large dose of the concentrated acid followed far more quickly than could be accounted for by the blood carrying the poison to the nervous centres; but Blake was among the first to point out that this doubt was not supported by facts carefully observed, since there is always a sufficient interval between the entry of the poison into the body and the first symptoms, to support the theory that the poison is absorbed in the usual manner. Even when Preyer injected a cubic centimetre of 60 per cent. acid into the jugular vein of a rabbit, twenty-nine seconds elapsed before the symptoms commenced. Besides, we have direct experiments showing that the acid--when applied to wounds in limbs, the vessels of which are tied, while the free nervous communication is left open--only acts when the ligature is removed. Magendie describes, in his usual graphic manner, how he killed a dog by injecting into the jugular vein prussic acid, and “the dog died instantly, as if struck by a cannon ball,” but it is probable that the interval of time was not accurately noted. A few seconds pass very rapidly, and might be occupied even by slowly pressing the piston of the syringe down, and in the absence of accurate measurements, it is surprising how comparatively long intervals of time are unconsciously shortened by the mind. In any case, this observation by Magendie has not been confirmed by the accurate tests of the more recent experimenters; and it is universally acknowledged that, although with strong doses of hydric cyanide injected into the circulation--or, in other words, introduced into the system--in the most favourable conditions for its speediest action, death occurs with appalling suddenness, yet that it takes a time sufficiently long to admit of explanation in the manner suggested. This has forensic importance, which will be again alluded to. Experiments on animals show that a large dose of a dilute acid kills quite as quickly as an equivalent dose of a stronger acid, and in some cases it even seems to act more rapidly. If the death does not take place within a few minutes, life may be prolonged for hours, and even, in rare cases, days, and yet the result be death. Coullon poisoned a dog with prussic acid; it lived for nineteen days, and then died; but this is quite an exceptional case, and when the fatal issue is prolonged beyond an hour, the chance of recovery is considerable.

§ 260. The length of time dogs poisoned by fatal doses survive, generally varies from two to fifteen minutes. The symptoms are convulsions, insensibility of the cornea, cessation of respiration, and, finally, the heart stops--the heart continuing to beat several minutes after the cessation of the respirations.[244] When the dose is short of a fatal one, the symptoms are as follows:--Evident giddiness and distress; the tongue is protruded, the breath is taken in short, hurried gasps, there is salivation, and convulsions rapidly set in, preceded, it may be, by a cry. The convulsions pass into paralysis and insensibility. After remaining in this state some time, the animal again wakes up, as it were, very often howls, and is again convulsed; finally, it sinks into a deep sleep, and wakes up well.

[244] N. Gréhant, Compt. rend., t. 109, pp. 502, 503.

Preyer noticed a striking difference in the symptoms after section of the vagus in animals, which varied according to whether the poison was administered by the lungs, or subcutaneously. In the first case, if the dose is small, the respirations are diminished in frequency; then this is followed by normal breathing; if the dose is larger, there is an increase in the frequency of the respirations. Lastly, if a very large quantity is introduced into the lungs, death quickly follows, with respirations diminished in frequency. On the other hand, when the poison is injected subcutaneously, small doses have no influence on the breathing; but with large doses, there is an increase in the frequency of the respirations, which sink again below the normal standard.

§ 261. =Symptoms in Man.=--When a fatal but not excessive dose of either potassic or hydric cyanide is taken, the sequence of symptoms is as follows:--Salivation, with a feeling of constriction in the throat, nausea, and occasionally vomiting. After a few minutes a peculiar constricting pain in the chest is felt, and the breathing is distinctly affected. Giddiness and confusion of sight rapidly set in, and the person falls to the ground in convulsions similar to those of epilepsy. The convulsions are either general, or attacking only certain groups of muscles; there is often true trismus, and the jaws are so firmly closed that nothing will part them. The respiration is peculiar, the inspiration is short, the expiration prolonged,[245] and between the two there is a long interval ever becoming more protracted as death is imminent. The skin is pale, or blue, or greyish-blue; the eyes are glassy and staring, with dilated pupils; the mouth is covered with foam, and the breath smells of the poison; the pulse, at first quick and small, sinks in a little while in frequency, and at length cannot be felt. Involuntary evacuation of fæces, urine, and semen is often observed, and occasionally there has been vomiting, and a portion of the vomit has been aspirated into the air-passages. Finally, the convulsions pass into paralysis, abolition of reflex sensibility, and gradual ceasing of the respiration. With large doses these different stages may occur, but the course is so rapid that they are merged the one into the other, and are undistinguishable. The shortest time between the taking of the acid and the commencement of the symptoms may be put at about ten seconds. If, however, a large amount of the vapour is inhaled at once, this period may be rather lessened. The interval of time is so short that any witnesses generally unintentionally exaggerate, and aver that the effects were witnessed before the swallowing of the liquid--“As the cup was at his lips”--“He had hardly drunk it,” &c. There is probably a short interval of consciousness, then come giddiness, and, it may be, a cry for assistance; and lastly, there is a falling down in convulsions, and a speedy death. Convulsions are not always present, the victim occasionally appears to sink lifeless at once. Thus, in a case related by Hufeland, a man was seen to swallow a quantity of acid, equivalent to 40 grains of the pure acid--that is, about forty times more than sufficient to kill him. He staggered a few paces, and then fell dead, without sound or convulsion.

[245] In a case quoted by Seidel (Maschka’s Handbuch, p. 321), a man, 36 years of age, four or five minutes after swallowing 150 mgrms. anhydrous HCN in spirits, lay apparently lifeless, without pulse or breathing. After a few minutes was noticed an extraordinary deep expiration, by which the ribs were drawn in almost to the spine, and the chest made quite hollow.

§ 262. The very short interval that may thus intervene between the taking of a dose of prussic acid and loss of consciousness, may be utilised by the sufferer in doing various acts, and thus this interval becomes of immense medico-legal importance. The question is simply this:--What can be done by a person in full possession of his faculties in ten seconds? I have found from experiment that, after drinking a liquid from a bottle, the bottle may be corked, the individual can get into bed, and arrange the bedclothes in a suitable manner; he may also throw the bottle away, or out of the window; and, indeed, with practice, in that short time a number of rapid and complicated acts may be performed. This is borne out both by experiments on animals and by recorded cases.

In Mr. Nunneley’s numerous experiments on dogs, one of the animals, after taking poison, “went down three or four steps of the stairs, saw that the door at the bottom was closed, and came back again.” A second went down, came up, and went again down the steps of a long winding staircase, and a third retained sufficient vigour to jump over another dog, and then leap across the top of a staircase.

In a remarkable case related by Dr. Guy,[246] in which a young man, after drinking more wine than usual, was seized by a sudden impulse to take prussic acid, and drank about 2 drachms, producing symptoms which, had it not been for prompt treatment, would, in all probability, have ended fatally--the interval is again noteworthy. After taking the poison in bed, he rose, walked round the foot of a chest of drawers, standing within a few yards of the bedside, placed the stopper firmly in the bottle, and then walked back to bed with the intention of getting into it; but here a giddiness seized him, and he sat down on the edge, and became insensible.

[246] Forensic Medicine, 4th ed., p. 615.

A case related by Taylor is still stronger. A woman, after swallowing a fatal dose of essence of almonds, went to a well in the yard, drew water, and drank a considerable quantity. She then ascended two flights of stairs and called her child, again descended a flight of stairs, fell on her bed, and died within half an hour from the taking of the poison.

Nevertheless, these cases and similar ones are exceptional, and only show what is possible, not what is usual, the rule being that after fatal doses no voluntary act of significance--save, it may be, a cry for assistance--is performed.[247]

[247] Dr. J. Autal, a Hungarian chemist, states that cobalt nitrate is an efficacious antidote to poisoning by either HCN or KCN. The brief interval between the taking of a fatal dose and death can, however, be rarely utilised.--Lancet, Jan. 16, 1894.

§ 263. =Chronic poisoning by hydric cyanide= is said to occur among photographers, gilders, and those who are engaged daily in the preparation or handling of either hydric or potassic cyanides. The symptoms are those of feeble poisoning, headache, giddiness, noises in the ears, difficult respiration, pain over the heart, a feeling of constriction in the throat, loss of appetite, nausea, obstinate constipation, full pulse, with pallor and offensive breath. Koritschoner[248] has made some observations on patients who were made to breathe at intervals, during many weeks, prussic acid vapour, with the idea that such a treatment would destroy the tubercle bacilli. Twenty-five per cent. of those treated in this way suffered from redness of the pharynx, salivation, headache, nausea, vomiting, slow pulse, and even albuminuria.

[248] Wiener klin. Woch., 1891.

§ 264. =Post-mortem Appearances.=[249]--If we for the moment leave out of consideration any changes which may be seen in the stomach after doses of potassic cyanide, then it may be affirmed that the pathological changes produced by hydric and potassic cyanides mainly coincide with those produced by suffocation. The most striking appearance is the presence of bright red spots; these bright red spots or patches are confined to the surface of the body, the blood in the deeper parts being of the ordinary venous hue, unless, indeed, an enormous dose has been taken; in that case the whole mass of blood may be bright red; this bright colour is due, according to Kobert, to the formation of cyanmethæmoglobin. The lungs and right heart are full of blood, and there is a backward engorgement produced by the pulmonic block. The veins of the neck and the vessels of the head generally are full of blood, and, in like manner, the liver and kidneys are congested. In the mucous membrane of the bronchial tubes there is a bloody foam, the lungs are gorged, and often œdematous in portions; ecchymoses are seen in the pleura and other serous membranes; and everywhere, unless concealed by putrefaction, or some strong-smelling ethereal oil, there is an odour of hydric cyanide.

[249] Hydric cyanide has, according to C. Brame, a remarkable antiseptic action, and if administered in sufficient quantity to animals, preserves them after death for a month. He considers that there is some more or less definite combination with the tissues.

Casper has rightly recommended the head to be opened and examined first, so as to detect the odour, if present, in the brain. The abdominal and chest cavities usually possess a putrefactive smell, but the brain is longer conserved, so that, if this course be adopted, there is a greater probability of detecting the odour.

The stomach in poisoning by hydric cyanide is not inflamed, but if alcohol has been taken at the same time, or previously, there may be more or less redness.

In poisoning by potassic cyanide, the appearances are mainly the same as those just detailed, with, it may be, the addition of caustic local action. I have, however, seen, in the case of a gentleman who drank accidentally a considerable dose of potassic cyanide just after a full meal, not the slightest trace of any redness, still less of corrosion. Here the contents of the stomach protected the mucous membrane, or possibly the larger amount of acid poured out during digestion sufficiently neutralised the alkali. Potassic cyanide, in very strong solution, may cause erosions of the lips, and the caustic effect may be traced in the mouth, throat, gullet, to the stomach and duodenum; but this is unusual, and the local effects are, as a rule, confined to the stomach and duodenum. The mucous membrane is coloured blood-red, reacts strongly alkaline,[250] is swollen, and it may be even ulcerated. The upper layers of the epithelium are also often dyed with the colouring-matter of the blood, which has been dissolved out by the cyanide. This last change is a post-mortem effect, and can be imitated by digesting the mucous membrane of a healthy stomach in a solution of cyanide. The intensity of these changes are, of course, entirely dependent on the dose and emptiness of the stomach. If the dose is so small as just to destroy life, there may be but little redness or swelling of the stomach, although empty at the time of taking the poison. In those cases in which there has been vomiting, and a part of the vomit has been drawn into the air-passages, there may be also inflammatory changes in the larynx. If essence of almonds has been swallowed, the same slight inflammation may be seen which has been observed with other essential oils, but no erosion, no strong alkaline reaction, nor anything approaching the effects of the caustic cyanide.

[250] The following case came under my own observation:--A stout woman, 35 years of age, the wife of a French polisher, drank, in a fit of rage, a solution of cyanide of potassium. It was estimated that about 15 grains of the solid substance were swallowed. She died within an hour. The face was flushed, the body not decomposed; the mouth smelt strongly of cyanide; the stomach had about an ounce of bloody fluid in it, and was in a most intense state of congestion. There was commencing fatty degeneration of the liver, the kidneys were flabby, and the capsule adherent. The contents of the stomach showed cyanide of potassium, and the blood was very fluid. The woman was known to be of intemperate habits.

In poisoning by bitter almonds no inflammatory change in the mucous membrane of the coats of the stomach would be anticipated, yet in one recorded case there seems to have been an eroded and inflamed patch.

§ 265. =Tests for Hydrocyanic Acid and Cyanide of Potassium.=--(1.) The addition of silver nitrate to a solution containing prussic acid, or a soluble cyanide,[251] produces a precipitate of argentic cyanide. 100 parts of argentic cyanide are composed of 80·60 Ag and 19·4 CN, equivalent to 20·1 HCN. It is a white anhydrous precipitate, soluble either in ammonia or in a solution of cyanide of potassium. It is soluble in hot dilute nitric acid, but separates on cooling. A particle of silver cyanide, moistened with strong ammonia, develops needles; silver chloride treated similarly, octahedral crystals. It is insoluble in water. Upon ignition it is decomposed into CN and metallic silver, mixed with a little paracyanide of silver.

[251] In the case of testing in this way for the alkaline cyanides, the solution must contain a little free nitric acid.

A very neat process for the identification of cyanide of silver is the following:--Place the perfectly dry cyanide in a closed or sealed tube, containing a few crystals of iodine. On heating slightly, iodide of cyanogen is sublimed in beautiful needles. These crystals again may be dissolved in a dilute solution of potash, a little ferrous sulphate added, and hydrochloric acid, and in this way Prussian blue produced. If the quantity to be tested is small, the vapour of the acid may be evolved in a very short test-tube, the mouth of which is closed by the ordinary thin discs of microscopic glass, the under surface of which is moistened with a solution of nitrate of silver; the resulting crystals of silver cyanide are very characteristic, and readily identified by the microscope.

(2.) If, instead of silver nitrate, the disc be moistened with a solution of sulphate of iron (to which has been added a little potash), and exposed to the vapour a short time, and then some dilute hydrochloric acid added, the moistened surface first becomes yellow, then green, lastly, and permanently, blue. No other blue compound of iron (with the exception of Prussian blue) is insoluble in dilute hydrochloric acid.

(3.) A third, and perhaps the most delicate of all, is the so-called sulphur test. A yellow sulphide of ammonium, containing free sulphur, is prepared by saturating ammonia by SH₂, first suspending in the fluid a little finely-precipitated sulphur (or an old, ill-preserved solution of sulphide of ammonium may be used). Two watch-glasses are now taken; in the one the fluid containing prussic acid is put, and the second (previously moistened with the sulphide of ammonium described) is inverted over it. The glasses are conveniently placed for a few minutes in the water-oven; the upper one is then removed, the moist surface evaporated to dryness in the water-bath, a little water added, and then a small drop of solution of chloride of iron. If hydrocyanic acid is present, the sulphocyanide of iron will be formed of a striking blood-red colour.

(4.) The reaction usually called Schönbein’s, or Pagenstecher and Schönbein’s[252] (but long known,[253] and used before the publication of their paper), consists of guaiacum paper, moistened with a very dilute solution of sulphate of copper (1 : 2000). This becomes blue if exposed to the vapour of hydrocyanic acid. Unfortunately, the same reaction is produced by ammonia, ozone, nitric acid, hypochlorous acid, iodine, bromine, chromate of potash, and other oxidising agents, so that its usefulness is greatly restricted.

[252] Neues Repert. de Pharm., 18, 356.

[253] This reaction (with tincture of guaiacum and copper) has been long known. “I remember a pharmaceutist, who attended my father’s laboratory, showing me this test in 1828 or 1829.”--Mohr’s Toxicologie, p. 92.

(5.) A very delicate test for prussic acid is as follows:--About one-half centigrm. of ammonia, ferrous sulphate (or other pure ferrous salt), and the same quantity of uranic nitrate, are dissolved in 50 c.c. of water, and 1 c.c. of this test-liquid is placed in a porcelain dish. On now adding a drop of a liquid containing the smallest quantity of prussic acid, a grey-purple colour, or a distinct purple precipitate is produced.[254]

[254] M. Carey Lea, Amer. Journ. of Science [3], ix. pp. 121-123; J. C. Society, 1876, vol. i. p. 112.

(6.) A hot solution of potassic cyanide, mixed with picric acid, assumes a blood-red colour, due to the formation of picro-cyanic acid. Free HCN does not give this reaction, and therefore must first be neutralised by an alkali.

(7.) =Schönbein’s Test.=--To a few drops of defibrinated ox-blood are added a few drops of the carefully-neutralised distillate supposed to contain prussic acid, and then a little neutral peroxide of hydrogen is added. If the distillate contains no prussic acid, then the mixture becomes of a bright pure red and froths strongly; if, on the other hand, a trace of prussic acid be present, the liquid becomes brown and does not froth, or only slightly does so.

(8.) =Kobert’s Test.=--A 1-4 per cent. solution of blood, to which a trace of ferridcyanide of potassium is added, is prepared, and the neutralised distillate added to this solution. If hydric cyanide be present, then the liquid becomes of a bright red colour, and, examined spectroscopically, instead of the spectrum of methæmoglobin, will be seen the spectrum of cyanmethæmoglobin. Kobert proposes to examine the blood of the poisoned, for the purpose of diagnosis, during life. A drop of blood from a healthy person, and a drop of blood from the patient, are examined side by side, according to the process just given.

§ 266. =Separation of Hydric Cyanide or Potassic Cyanide from Organic Matters, such as the Contents of the Stomach, &c.=--It is very necessary, before specially searching for hydric cyanide in the contents of the stomach, to be able to say, by careful and methodical examination, whether there are or are not any fragments of bitter almonds, of apples, peaches, or other substance likely to produce hydric cyanide. If potassic cyanide has been taken, simple distillation will always reveal its presence, because it is found partly decomposed into hydric cyanide by the action of the gastric acids. Nevertheless, an acid should always be added, and if, as in the routine process given at p. 48, there is reasonable doubt for suspecting that there will be no cyanide present, it will be best to add tartaric acid (for this organic acid will in no way interfere with subsequent operations), and distil, as recommended, in a vacuum. If, however, from the odour and from the history of the case, it is pretty sure to be a case of poisoning by hydric or potassic cyanide, then the substances, if fluid, are at once placed in a retort or flask, and acidified with a suitable quantity of sulphuric acid, or if the tissues or other solid matters are under examination, they are finely divided, or pulped, and distilled, after acidifying with sulphuric acid as before. It may be well here, as a caution, to remark that the analyst must not commit the unpardonable error of first producing a cyanide by reagents acting on animal matters, and then detecting as a poison the cyanide thus manufactured. If, for example, a healthy liver is carbonised by nitric acid, saturated with potash, and then burnt up, cyanide of potassium is always one of the products; and, indeed, the ashes of a great variety of nitrogenous organic substances may contain cyanides--cyanides not pre-existing, but manufactured by combination. By the action of nitric acid even on sugar,[255] hydric cyanide is produced.

[255] Chemical News, 68, p. 75.

The old method of distillation was to distil by the gentle heat of a water-bath, receiving the distillate in a little weak potash water, and not prolonging the process beyond a few hours. The experiments of Sokoloff, however, throw a grave doubt on the suitability of this simple method for quantitative results.

N. Sokoloff[256] recommends the animal substances to be treated by water strongly acidified with hydric sulphate, and then to be distilled in the water-bath for from two to three days; or to be distilled for twenty-four hours, by the aid of an oil-bath, at a high temperature. He gives the following example of quantitative analysis by the old process of merely distilling for a few hours, and by the new:--

[256] Ber. d. deutsch. chem. Gesellsch., Berlin, ix. p. 1023.

=Old Process.=--(1.) Body of a hound--age, 2 years; weight, 5180 grms.; dose administered, 57 mgrms. HCN; death in fifteen minutes. After five days there was found in the saliva 0·6 mgrm., stomach 3·2 mgrms., in the rest of the intestines 2·6 mgrms., in the muscles 4·1--total, 10·5.

(2.) Weight of body, 4000 grms.; dose given, 38 mgrms.; death in eleven minutes. After fifteen days, in the saliva 0·8, in the stomach 7·2, in the rest of the intestines 2·2, in the muscles 3·2--total, 13·4.

=New Process.=--Weight of body, 5700 grams; dose, 57 mgrms.; death in twenty-four minutes. After fifteen days, in the saliva 1·1 mgrm., in the stomach 2·6, in the rest of the intestines 9·6, in the muscles 31·9, and in the whole, 45·2 mgrms. Duration of process, thirteen hours.

From a second hound, weighing 6800 grms.; dose, 67 mgrms.; 25·1 mgrms. were separated three days after death.

From a third hound, weighing 5920 grms.; dose, 98 mgrms.; after forty days, by distillation on a sand-bath, there were separated 2·8 mgrms. from the saliva, 4·8 from the stomach, 16·8 from the intestines, 23·6 from the muscles--total, 48 mgrms.

It would also appear that he has separated 51·2 mgrms. of anhydrous acid from the corpse of a dog which had been poisoned by 57 mgrms. of acid, and buried sixty days.[257]

[257] Without wishing to discredit the statements of M. Sokoloff, we may point out that a loss of half-a-dozen mgrms. only appears rather extraordinary.

From another canine corpse, three days laid in an oven, and left for twenty-seven days at the ordinary temperature, 5·1 mgrms. were recovered out of a fatal dose of 38 mgrms.

The estimation was in each case performed by titrating the distillate with argentic nitrate, the sulphur compounds having been previously got rid of by saturating the distillate with KHO, and precipitating by lead acetate.

Venturoli[258] has, on the contrary, got good quantitative results without distillation at all. A current of pure hydrogen gas is passed through the liquid to be tested and the gas finally made to bubble through silver nitrate. He states that the whole of the hydric cyanide present is carried over in an hour. Metallic cyanides must be decomposed by sulphuric acid or tartaric acid. Mercury cyanide must be decomposed with SH₂, the solution acidified with tartaric acid, neutralised with freshly precipitated calcic carbonate to fix any ferro- or ferri-cyanides present, and hydrogen passed in and the issuing gases led first through a solution of bismuth nitrate to remove SH₂ and then into the silver solution.

[258] L’Orosi. xv. 85-88.

§ 267. =How long after Death can Hydric or Potassic Cyanides be Detected?=--Sokoloff appears to have separated prussic acid from the body of hounds at very long periods after death--in one case sixty days. Dragendorff recognised potassic cyanide in the stomach of a hound after it had been four weeks in his laboratory,[259] and in man eight days after burial. Casper also, in his 211th case, states that more than 18 mgrms. of anhydrous prussic acid were obtained from a corpse eight days after death.[260] Dr. E. Tillner[261] has recognised potassic cyanide in a corpse four months after death. Lastly, Struve[262] put 300 grms. of flesh, 400 of common water, and 2·378 of KCy in a flask, and then opened the flask after 547 days. The detection was easy, and the estimation agreed with the amount placed there at first. So that, even in very advanced stages of putrefaction, and at periods after death extending beyond many months, the detection of prussic acid cannot be pronounced impossible.

[259] Dragendorff, G., Beitr. zur gericht. Chem., p. 59.

[260] Casper’s Pract. Handbuch der gerichtlichen Medicin, p. 561.

[261] Vierteljahr. f. gerichtl. Med., Berlin, 1881, p. 193.

[262] Zeitschrift f. anal. Chemie, von Fresenius, 1873, xii. p. 4.

§ 268. =Estimation of Hydrocyanic Acid or Potassic Cyanide.=--In all cases, the readiest method of estimating prussic acid (whether it be in the distillate from organic substances or in aqueous solution) is to saturate it with soda or potash, and titrate the alkaline cyanide thus formed with nitrate of silver. The process is based on the fact that there is first formed a soluble compound (KCy, AgCy), which the slightest excess of silver breaks up, and the insoluble cyanide is at once precipitated. If grains are used, 17 grains of nitrate of silver are dissolved in water, the solution made up to exactly 1000 grain measures, each grain measure equalling ·0054 grain of anhydrous hydrocyanic acid. If grammes are employed, the strength of the nitrate of silver solution should be 1·7 grm. to the litre, each c.c. then = ·0054 hydrocyanic acid, or ·01302 grm. of potassic cyanide.

Essential oil of bitter almonds may also be titrated in this way, provided it is diluted with sufficient spirit to prevent turbidity from separation of the essential oil. If hydrocyanic acid is determined gravimetrically (which is sometimes convenient, when only a single estimation is to be made), it is precipitated as cyanide of silver, the characters of which have been already described.

§ 269. =Case of Poisoning by Bitter Almonds.=--Instances of poisoning by bitter almonds are very rare. The following interesting case is recorded by Maschka:--

A maid-servant, 31 years of age, after a quarrel with her lover, ate a quantity of bitter almonds. In a few minutes she sighed, complained of being unwell and faint; she vomited twice, and, after about ten minutes more had elapsed, fell senseless and was convulsed. An hour afterwards, a physician found her insensible, the eyes rolled upwards, the thumb clenched within the shut fists, and the breathing rattling, the pulse very slow. She died within an hour-and-a-half from the first symptoms.

The autopsy showed the organs generally healthy, but all, save the liver, exhaling a faint smell of bitter almonds. The right side of the heart was full of fluid dark blood, the left was empty. Both lungs were rich in blood, which smelt of prussic acid. The stomach was not inflamed--it held 250 grms. of a yellow fluid, containing white flocks smelling of bitter almond oil. In the most dependent portion of the stomach there was a swollen patch of mucous membrane, partially denuded of epithelium. The mucous membrane of the duodenum was also swollen and slightly red. The contents of the stomach were acid, and yielded, on distillation, hydride of benzole and hydric cyanide. Residues of the almonds themselves were also found, and the whole quantity taken by the woman from various data was calculated to be 1200 grains of bitter almonds, equal to 43 grains of amygdalin, or 2·5 grains of pure hydric cyanide.

Poisonous Cyanides other than Hydric and Potassic Cyanides.

§ 270. The action of both sodic and ammonic cyanides is precisely similar to that of potassic cyanide. With regard to ammonic cyanide, there are several experiments by Eulenberg,[263] showing that its vapour is intensely poisonous.

[263] Gewerbe Hygiene, p. 385.

A weak stream of ammonic cyanide vapour was passed into glass shades, under which pigeons were confined. After a minute, symptoms of distress commenced, then followed convulsions and speedy death. The post-mortem signs were similar to those produced by prussic acid, and this substance was separated from the liver and lungs.

§ 271. With regard to the double cyanides, all those are poisonous from which hydric cyanide can be separated through dilute acids, while those which, like potassic ferro-cyanide, do not admit of this decomposition, may be often taken with impunity, and are only poisonous under certain conditions.

Sonnenschein records the death of a colourist, after he had taken a dose of potassic ferro-cyanide and then one of tartaric acid; and Volz describes the death of a man, who took potassic ferro-cyanide and afterwards equal parts of nitric and hydrochloric acids. In this latter case, death took place within the hour, with all the symptoms of poisoning by hydric cyanide; so that it is not entirely true, as most text-books declare, that ferro-cyanide is in no degree poisonous. Carbon dioxide will decompose potassic ferro-cyanide at 72°-74°, potass ferrous cyanide being precipitated--K₂Fe₂(CN)₆. A similar action takes place if ferro-cyanide is mixed with a solution of peptone and casein, and digested at blood heat[264] (from 37° to 40° C.), so that it is believed that when ferro-cyanide is swallowed HCN is liberated, but the quantity is usually so small at any given moment that no injury is caused: but there are conditions in which it may kill speedily.[265]

[264] Autenrieth, Arch. Pharm., 231, 99-109.

[265] The presence of ferro-cyanide is easily detected. The liquid is, if necessary, filtered and then acidified with hydrochloric acid and a few drops of ferric chloride added; if the liquid contains ferro-cyanide, there is immediate production of Prussian blue. It may happen that potassic or sodic cyanide has been taken as well as ferro-cyanide, and it will be necessary then to devise a process by which only the prussic acid from the simple cyanide is distilled over. According to Autenrieth, if sodium hydrocarbonate is added to the liquid in sufficient quantity and the liquid distilled, the hydric cyanide that comes over is derived wholly from the sodium or potassium cyanide. Should mercury cyanide and ferro-cyanide be taken together, then this process requires modification; bicarbonate of soda is added as before, and then a few c.c. of water saturated with hydric sulphide; under these circumstances, only the hydric cyanide derived from the mercury cyanide distils over. If the bicarbonate of soda is omitted, the distillate contains hydric cyanide derived from the ferro-cyanide.

=Mercuric cyanide=, it has been often said, acts precisely like mercuric chloride (corrosive sublimate), and a poisonous action is attributed to it not traceable to cyanogen; but this is erroneous teaching. Bernard[266] declares that it is decomposed by the gastric juice, and hydric cyanide set free; while Pelikan puts it in the same series as ammonic and potassic cyanides. Lastly, Tolmatscheff,[267] by direct experiment, has found its action to resemble closely that of hydric cyanide.[268]

[266] Substances Toxiques, pp. 66-103.

[267] “Einige Bemerkungen über die Wirkung von Cyanquecksilber,” in Hoppe-Seyler’s Med. Chem. Untersuchungen, 2 Heft, p. 279.

[268] Mercury cyanide may be detected in a liquid after acidifying with tartaric acid, and adding a few c.c. of SH₂ water and then distilling. S. Lopes suggests another process: the liquid is acidified with tartaric acid, ammonium chloride added in excess, and the liquid is distilled. A double chloride of ammonium and mercury is formed, and HCN distils over with the steam.--J. Pharm., xxvii. 550-553.

=Silver cyanide= acts, according to the experiments of Nunneley, also like hydric cyanide, but very much weaker.

=Hydric sulphocyanide= in very large doses is poisonous.

=Potassic sulphocyanide=, according to Dubreuil and Legros,[269] if subcutaneously injected, causes first local paralysis of the muscles, and later, convulsions.

[269] Compt. rend., t. 64, 1867, p. 561.

=Cyanogen chloride= (CNCl) and also the compound (C₃N₃Cl₃)--the one a liquid, boiling at 15°, the other a solid, which may be obtained in crystals--are both poisonous, acting like hydric cyanide.

=Methyl cyanide= is a liquid obtained by distillation of a mixture of calcic methyl sulphate and potassic cyanide. It boils at 77°, and is intensely poisonous. Eulenberg[270] has made with this substance several experiments on pigeons. An example of one will suffice:--A young pigeon was placed under a glass shade, into which methyl cyanide vapour, developed from calcic methyl sulphate and potassic cyanide, was admitted. The pigeon immediately became restless, and the fæces were expelled. In forty seconds it was slightly convulsed, and was removed after a few minutes’ exposure. The pupils were then observed not to be dilated, but the respiration had ceased; the legs were feebly twitching; the heart still beat, but irregularly; a turbid white fluid dropped out of the beak, and after six minutes life was extinct.

[270] Gewerbe Hygiene, p. 392.

The pathological appearances were as follows:--In the beak much watery fluid; the membranes covering the brain weakly injected; the plexus venosus spinalis strongly injected; in the region of the cervical vertebra a small extravasation between the dura mater and the bone; the right lung of a clear cherry-red colour, and the left lung partly of the same colour, the parenchyma presented the same hue as the surface; on section of the lungs a whitish froth exuded from the cut surface. In the cellular tissue of the trachea, there were extravasations 5 mm. in diameter; the mucous membrane of the air-passages was pale; the right ventricle and the left auricle of the heart were filled with coagulated and fluid dark red blood; liver and kidneys normal; the blood dark red and very fluid, becoming bright cherry-red on exposure to the air; blood corpuscles unchanged. Cyanogen was separated, and identified from the lungs and the liver.

=Cyanuric acid= (C₃O₃N₃H₃), one of the decomposition products obtained from urea, is poisonous, the symptoms and pathological effects closely resembling those due to hydric cyanide. In experiments on animals, there has been no difficulty in detecting prussic acid in the lungs and liver after poisoning by cyanuric acid.

XIII.--Phosphorus.

§ 272. =Phosphorus.=--Atomic weight 31, specific gravity 1·77 to 1·840. Phosphorus melts at from 44·4° to 44·5° to a pale yellow oily fluid. The boiling-point is about 290°.

The phosphorus of commerce is usually preserved under water in the form of waxy, semi-transparent sticks; if exposed to the air white fumes are given off, luminous in the dark, with a peculiar onion-like odour. On heating phosphorus it readily inflames, burning with a very white flame.

At 0° phosphorus is brittle; the same quality may be imparted to it by a mere trace of sulphur. Phosphorus may be obtained in dodecahedral crystals by slowly cooling large melted masses. It may also be obtained crystalline by evaporating a solution in bisulphide of carbon or hot naphtha in a current of carbon dioxide. It is usually stated to be absolutely insoluble in water, but Julius Hartmann[271] contests this, having found in some experiments that 100 grms. of water digested with phosphorus for sixty-four hours at 38·5° dissolved ·000127 grm. He also investigated the solvent action of bile, and found that 100 grms. of bile under the same conditions, dissolved ·02424 grm., and that the solubility of phosphorus rose both in water and bile when the temperature was increased. Phosphorus is somewhat soluble in alcohol and ether, and also, to some extent, in fatty and ethereal oils; but the best solvent is carbon disulphide.

[271] Zur acuten Phosphor-Vergiftung, Dorpat, 1866.

The following is the order of solubility in certain menstrua, the figures representing the number of parts by weight of the solvent required to dissolve 1 part of phosphorus:--

Carbon Disulphide, 4 Almond Oil, 100 Concentrated Acetic Acid,[272] 100 Ether, 250 Alcohol, specific gravity ·822, 400 Glycerin, 588

[272] Phosphorus is very little soluble in cold acetic acid, and the solubility given is only correct when the boiling acid acts for some time on the phosphorus.

Phosphorus exists in, or can be converted into, several allotropic modifications, of which the red or amorphous phosphorus is the most important. This is effected by heating it for some time, in the absence of air, from 230° to 235°. It is not poisonous.[273] Commercial red phosphorus does, however, contain very small quantities of unchanged or ordinary phosphorus--according to Fresenius, from ·6 per cent. downwards; it also contains phosphorous acid, and about 4·6 per cent. of other impurities, among which is graphite.[274]

[273] A hound took 200 grms. of red phosphorus in twelve days, and remained healthy.--Sonnenschein.

[274] Schrotter, Chem. News, vol. xxxvi. p. 198.

§ 273. =Phosphuretted Hydrogen.=--=Phosphine= (PH₃), mol. weight 34, specific gravity 1·178, percentage composition, phosphorus 91·43, hydrogen 8·57 by weight. The absolutely pure gas is not spontaneously inflammable, but that made by the ordinary process is so. It is a colourless, highly poisonous gas, which does not support combustion, but is itself combustible, burning to phosphoric acid (PH₃ + 2O₂ = PO₄H₃). Extremely dangerous explosive mixtures may be made by combining phosphine and air or oxygen. Phosphine, when quite dry, burns with a white flame, but if mixed with aqueous vapour, it is green; hence a hydrogen flame containing a mixture of PH₃ possesses a green colour.

If sulphur is heated in a stream of phosphine, hydric sulphide and sulphur phosphide are the products. Oxides of the metals, heated with phosphine, yield phosphides with formation of water. Iodine, warmed in phosphine, gives white crystals of iodine phosphonium, and biniodide of phosphorus, 5I + 4PH₃ = 3PIH₄ + PI₂. Chlorine inflames the gas, the final result being hydric chloride and chloride of phosphorus, PH₃ + 8Cl = 3ClH + PCl₅. One of the most important decompositions for our purpose is the action of phosphine on a solution of nitrate of silver; there is a separation of metallic silver, and nitric and phosphoric acids are found in solution, thus--8AgNO₃ + PH₃ + 4OH₂ = 8Ag + 8HNO₃ + PO₄H₃. This is, however, rather the end reaction; for, at first, there is a separation of a black precipitate composed of phosphor-silver. The excess of silver can be separated by hydric chloride, and the phosphoric acid made evident by the addition of molybdic acid in excess.

§ 274. =The medicinal preparations of phosphorus= are not numerous; it is usually prescribed in the form of pills, made by manufacturers of coated pills on a large scale. The pills are composed of phosphorus, balsam of Tolu, yellow wax, and curd soap, and 3 grains equal 1/30 grain of phosphorus. There is also a phosphorated oil, containing about 1 part of phosphorus in 100; that of the French Pharmacopœia is made with 1 part of dried phosphorus dissolved in 50 parts of warm almond oil; that of the German has 1 part in 80; the strength of the former is therefore 2 per cent., of the latter 1·25 per cent. The medicinal dose of phosphorus is from 1/100 to 1/30 grain.

§ 275. =Matches and Vermin Pastes.=--An acquaintance with the percentage of phosphorus in the different pastes and matches of commerce will be found useful. Most of the vermin-destroying pastes contain from 1 to 2 per cent. of phosphorus.

A phosphorus paste that was fatal to a child,[275] and gave rise to serious symptoms in others, was composed as follows:--

[275] Casper’s 204th case.

Per cent. Phosphorus, 1·4 Flowers of sulphur, 42·2 Flour, 42·2 Sugar, 14·2 ------ 100·00

Three common receipts give the following proportions:--

Per cent. Phosphorus, 1·5 Lard, 18·4 Sugar, 18·4 Flour, 61·7 ------ 100·00

Per cent. Phosphorus, 1·2 Warm water, 26·7 Rye flour, 26·7 Melted butter, 26·7 Sugar, 18·7 ------ 100·00

Per cent. Phosphorus, 1·6 Nut oil, 15·7 Warm water, 31·5 Flour, 31·5 Sugar, 19·7 ------ 100·00

A very common phosphorus paste, to be bought everywhere in England, is sold in little pots; the whole amount of phosphorus contained in these varies from ·324 to ·388 grm. (5 to 6 grains), the active constituent being a little over 4 per cent. Matches differ much in composition. Six matchheads, which had been placed in an apple for criminal purposes, and were submitted to Tardieu, were found to contain 20 mgrms. of phosphorus--i.e., ·33 grm. in 100. Mayet found in 100 matches 55 mgrms. of phosphorus. Gonning[276] analysed ten different kinds of phosphorus matches with the following result:--Three English samples contained in 100 matches 34, 33, and 32 mgrms. of phosphorus: a Belgian sample, 38 mgrms.; and 5 others of unknown origin, 12, 17, 28, 32, and 41 mgrms. respectively. Some of the published formularies are as follows:--

[276] Nederlandsch Tijdschr. voor Geneesk., Afl. i., 1866.

(1.) Glue, 6 parts. Phosphorus, 4 „ or 14·4 per cent. Nitre, 10 „ Red ochre, 5 „ Blue smalts, 2 „

(2.) Phosphorus, 9 parts, or 16·3 per cent. Gum, 16 „ Nitre, 14 „ Smalts, 16 „

(3.) Phosphorus, 4 parts, or 14·4 per cent. Glue, 6 „ Nitre, 10 „ Red lead, 5 „ Smalts, 2 „

(4.) Phosphorus, 17 parts, or 17 per cent. Glue, 21 „ Nitre, 38 „ Red lead, 24 „

Phosphorus poisoning by matches will, however, shortly become very rare, for those containing the ordinary variety of phosphorus are gradually being superseded by matches of excellent quality, which contain no phosphorus whatever.

§ 276. =Statistics.=--The following table gives the deaths for ten years from phosphorus poisoning in England and Wales:--

DEATHS FROM PHOSPHORUS IN ENGLAND AND WALES DURING THE TEN YEARS ENDING 1892.

ACCIDENT OR NEGLIGENCE.

Ages, 1-5 5-15 15-25 25-65 65 and Total above Males, 11 1 2 8 ... 22 Females, 15 2 11 5 ... 33 ------------------------------------------- Totals, 26 3 13 13 ... 55 -------------------------------------------

SUICIDE.

Ages, 5-15 15-25 25-65 65 and Total above Males, 1 6 20 1 28 Females, 6 33 24 1 64 ------------------------------------- Totals, 7 39 44 2 92 -------------------------------------

Phosphorus as a cause of death through accident or negligence occupies the eighth place among poisons, and as a cause of suicide the ninth.

A far greater number of cases of poisoning by phosphorus occur yearly in France and Germany than in England. Phosphorus may be considered as the favourite poison which the common people on the Continent employ for the purpose of self-destruction. It is an agent within the reach of anyone who has 2 sous in his pocket, wherewith to buy a box of matches, but to the educated and those who know the horrible and prolonged torture ensuing from a toxic dose of phosphorus, such a means of exit from life will never be favoured.

Otto Schraube[277] has collected 92 cases from Meischner’s work,[278] and added 16 which had come under his own observation, giving in all 108 cases. Seventy-one (or 65 per cent.) of these were suicidal--of the suicides 24 were males, 47 females (12 of the latter being prostitutes); 21 of the cases were those of murder, 11 were accidental, and in 3 the cause was not ascertained. The number of cases in successive years, and the kind of poison used, is given as follows:--

[277] Schmidt’s Jahrbuch der ger. Med., 1867, Bd. 186, S. 209-248.

[278] Die acute Phosphorose und einige Reflexionen über die acute gelbe Leberatrophie, &c., Inaug. Diss., Leipzig, 1864.

Phosphorus in Phosphorus Number of Cases. In the Years Substance, Matches. or as Paste.

15 1798-1850 13 2 36 1850-1860 15 21 41 1860-1864 6 35 16 1864-1867 5 11

Of the 108 cases, 18 persons recovered and 90 (or 83·3 per cent.) died.

Falck also has collected 76 cases of poisoning from various sources during eleven years; 55 were suicidal, 5 homicidal[279] (murders), and the rest accidental. Of the latter, 2 were caused by the use of phosphorus as a medicine, 13 by accidents due to phosphorus being in the house; in 1 case phosphorus was taken intentionally to try the effects of an antidote.[280] With regard to the form in which the poison was taken, 2 of the 76, as already mentioned, took it as prescribed by physicians, the remaining 74 were divided between poisonings by phosphorus paste (22) and matches (52) = 70 per cent. Of the 76 cases, 6 were children, 43 adult males, 13 adult females, and 14 adults, sex not given. Of the 76 cases, 42, or 55·3 per cent., died--a much smaller rate of mortality than that shown by Schraube’s collection.

[279] Dr. Dannenberg has shown by direct experiment that a poisonous dose of phosphorus may be introduced into spirits or coffee, and the mixture have but little odour or taste of phosphorus.--Schuchardt in Maschka’s Handbuch.

[280] Géry, “Ueber Terpentinessenz als Gegenmittel gegen Phosphor,” in Gaz. Hebd. de Méd., 2 sér., x. 2, 1873.

§ 277. =Fatal Dose.=--The smallest dose on record is that mentioned by Lobenstein Lobel, of Jena, where a lunatic died from taking 7·5 mgrms. (·116 grain). There are other cases clearly indicating that this small quantity may produce dangerous symptoms in a healthy adult.

§ 278. =Effects of Phosphorus.=--Phosphorus is excessively poisonous, and will destroy life, provided only that it enters the body in a fine state of division, but if taken in coarse pieces no symptoms may follow, for it has been proved that single lumps of phosphorus will go the whole length of a dog’s intestinal canal without causing appreciable loss of weight, and without destroying life.[281] Magendie injected oleum phosphoratum into the veins, and although the animals experimented on exhaled white fumes, and not a few died asphyxiated, yet no symptoms of phosphorus poisoning resulted--an observation confirmed by others--the reason being that the phosphorus particles in a comparatively coarse state of division were arrested in the capillaries of the lung, and may be said to have been, as it were, outside the body. On the other hand, A. Brunner,[282] working in L. Hermann’s laboratory, having injected into the veins phosphorus in such a fine emulsion that the phosphorus could pass the lung capillaries, found that there were no exhalations of white fumes, but that the ordinary symptoms of phosphorus poisoning soon manifested themselves. Phosphorus paste, by the method of manufacture, is in a state of extreme sub-division, and hence all the phosphorus pastes are extremely poisonous.

[281] Reveil, Ann. d’Hygiène Publ. (3), xii. p. 370.

[282] Arch. f. d. Ges. Physiologie, iii. p. 1.

§ 279. In a few poisons there is a difference, more or less marked, between the general symptoms produced on man, and those noticeable in the different classes of animals; but with phosphorus, the effects on animals appear to agree fairly with those witnessed most frequently in man. Tardieu (who has written perhaps the best and most complete clinical record of phosphorus poisoning extant) divides the cases under three classes, and to use his own words:--“I think it useful to establish that poisoning by phosphorus in its course, sometimes rapid, sometimes slow, exhibits in its symptoms three distinct forms--a common form, a nervous form, and a hæmorrhagic form. I recognise that, in certain cases, these three forms may succeed each other, and may only constitute periods of poisoning; but it is incontestable that each of them may show itself alone, and occupy the whole course of the illness produced by the poison.”[283] Premising that the common form is a blending of irritant, nervous, and hæmorrhagic symptoms, I adopt here in part Tardieu’s division. The name of “hæmorrhagic form” may be given to that in which hæmorrhage is the predominant feature, and the “nervous” to that in which the brain and spinal cord are from the first affected. There yet remain, however, a few cases which have an entirely anomalous course, and do not fall under any of the three classes.

[283] Étude Médico-Légale et Clinique sur l’Empoisonnement, Paris, 1875, p. 483.

From a study of 121 recorded cases of phosphorus poisoning, I believe the relative frequency of the different forms to be as follows:--The common form 83 per cent., hæmorrhagic 10 per cent., nervous 6 per cent., anomalous 1 per cent. The “anomalous” are probably over-estimated, for the reason that cases presenting ordinary features are not necessarily published, but others are nearly always chronicled in detail.

§ 280. =Common Form.=--At the moment of swallowing, a disagreeable taste and smell are generally experienced, and there may be immediate and intense pain in the throat, gullet, and stomach, and almost immediate retching and vomiting. The throat and tongue also may become swollen and painful; but in a considerable number of cases the symptoms are not at once apparent, but are delayed from one to six hours--rarely longer. The person’s breath may be phosphorescent before he feels in any way affected, and he may go about his business and perform a number of acts requiring both time and mental integrity. Pain in the stomach (which, in some of the cases, takes the form of violent cramp and vomiting) succeeds; the matters vomited may shine in the dark, and are often tinged with blood. Diarrhœa is sometimes present, sometimes absent; sleeplessness for the first night or two is very common. The pulse is variable, sometimes frequent, sometimes slow; the temperature in the morning is usually from 36·0° to 36·5°, in the evening 37° to 38°.

The next symptom is jaundice. I have notes of the exact occurrence of jaundice in 23 cases, as follows:--In 1 within twenty-four hours, in 3 within thirty-six hours, in 3 within two days, in 11 within three days, in 1 within four days, in 1 within five days, in 1 within nine days, in 1 within eighteen days, and in 1 within twenty-seven days; so that in about 78 per cent. jaundice occurred before the end of the third day. Out of 26 cases, in which the patients lived long enough for the occurrence of jaundice, in 3 (or 11 per cent.) it was entirely absent. In 132 cases recorded by Lewin, Meischner, and Heisler, jaundice occurred in 65, or about 49 per cent., but it must be remembered, that in many of these cases the individual died before it had time to develop. The jaundice having thoroughly pronounced itself, the system may be considered as not only under the influence of the toxic action of phosphorus, but as suffering in addition from all the accidents incidental to the retention of the biliary secretion in the blood; nor is there from this point any special difference between phosphorus poisoning and certain affections of the liver--such, for example, as acute yellow atrophy. There is retention of urine, sleeplessness, headache, frequent vomiting, painful and often involuntary evacuations from the bowels, and occasionally skin affections, such as urticaria or erythema. The case terminates either by acute delirium with fever, followed by fatal coma, or, in a few instances, coma comes on, and the patient passes to death in sleep without delirium. In this common form there is in a few cases, at the end of from twenty-four to thirty hours, a remission of the symptoms, and a non-medical observer might imagine that the patient was about to recover without further discomfort; but then jaundice supervenes, and the course is as described. Infants often do not live long enough for the jaundiced stage to develop, but die within twenty-four hours, the chief symptoms being vomiting and convulsions.

§ 281. =Hæmorrhagic Form.=--The symptoms set in as just detailed, and jaundice appears, but accompanied by a new and terrible train of events--viz., great effusion of blood. In some cases the blood has been poured out simultaneously from the nose, mouth, bladder, kidneys, and bowels. Among women there is excessive hæmorrhagia. The liver is found to be swollen and painful; the bodily weakness is great. Such cases are usually of long duration, and a person may die months after taking the poison from weakness, anæmia, and general cachexia. In many of its phases the hæmorrhagic form resembles scurvy, and, as in scurvy, there are spots of purpura all over the body.

§ 282. =The nervous form= is less common than the two forms just described. From the beginning, there are strange creeping sensations about the limbs, followed by painful cramps, repeated faintings, and great somnolence. Jaundice, as usual, sets in, erythematous spots appear on the skin, and, about the fifth day, delirium of an acute character breaks out, and lock-jaw and convulsions close the scene.

The following are one or two brief abstracts of anomalous cases in which symptoms are either wanting, or run a course entirely different from any of the three forms described:--

A woman, aged 20, took about 3 grains of phosphorus in the form of rat-paste. She took the poison at six in the evening, behaved according to her wont, and sat down and wrote a letter to the king. During the night she vomited once, and died the next morning at six o’clock, exactly twelve hours after taking the poison. There appear to have been no symptoms whatever, save the single vomiting, to which may be added that in the course of the evening her breath had a phosphorus odour and was luminous.[284]

[284] Casper’s 205th case.

A girl swallowed a quantity of phosphorus paste, but there were no marked symptoms until the fifth day, on which there was sickness and purging. She died on the seventh day. A remarkable blueness of the finger nails was observed a little before death, and was noticeable afterwards.[285]

[285] Taylor on Poisons, p. 277.

§ 283. =Sequelæ.=--In several cases in which the patients have recovered from phosphorus poisoning, there have been observed paralytic affections.[286] O. Bollinger has recorded a case in which paralysis of the foot followed;[287] in another, published by Bettelheim,[288] there were peculiar cerebral and spinal symptoms. Most of these cases are to be explained as disturbance or loss of function from small hæmorrhages in the nervous substance.

[286] See Gallavardin, Les Paralyses Phosphoriques, Paris, 1865.

[287] Deutsches Archiv f. klin. Med., Bd. 6, Hft. 1, S. 94, 1869.

[288] Wiener Med. Presse, 1868, No. 41.

§ 284. =Period at which the first Symptoms commence.=--The time when the symptoms commence is occasionally of importance from a forensic point of view. I find that out of 28 cases in which the commencement of evident symptoms--i.e., pain, or vomiting, or illness--is precisely recorded, in 8 the symptoms were described as either immediate or within a few minutes after swallowing the poison; in 6 the symptoms commenced within the hour; in 3 within two hours; in other 3 within four hours; and in 1 within six hours. One was delayed until the lapse of twelve hours, 1 from sixteen to eighteen hours, 1 two, and another five days. We may, therefore, expect that in half the cases which may occur, the symptoms will commence within the hour, and more than 80 per cent. within six hours.

§ 285. =Period of Death.=--In 129 cases death took place as follows:--In 17 within twenty-four hours, in 30 within two days, in 103 within seven days. Three patients lived eight days, 6 nine days, 13 ten days, 1 eleven days, 1 sixteen days, 1 seventeen days, and 1 survived eight months. It hence follows that 79·8 per cent. of the fatal cases die within the week.

§ 286. =Phosphorus Vapour.=--There are one or two cases on record of acute poisoning by phosphorus in the form of vapour. The symptoms are somewhat different from the effects produced by the finely-divided solid, and in general terms it may be said that phosphorus vapour is more apt to produce the rarer “nervous” form of poisoning than the solid phosphorus.

Bouchardat[289] mentions the case of a druggist who, while preparing a large quantity of rat-poison in a close room, inhaled phosphorus vapour. He fainted repeatedly, fell into a complete state of prostration, and died within a week.

[289] Annuaire de Thérap., 1874, p. 109; Schuchardt in Maschka’s Handbuch; also Schmidt’s Jahrbuch, 1846, Bd. 51, S. 101.

The following interesting case came under the observation of Professor Magnus Huss:--A man, thirty-nine years old, married, was admitted into the Seraphin-Lazareth, Stockholm, on the 2nd of February 1842. He had been occupied three years in the manufacture of phosphorus matches, and inhabited the room in which the materials were preserved. He had always been well-conducted in every way, and in good health, until a year previously, when a large quantity of the material for the manufacture of the matches accidentally caught fire and exploded. In his endeavours to extinguish the flames, he breathed a large quantity of the vapour, and he fell for a time unconscious. The spine afterwards became so weak that he could not hold himself up, and he lost, in a great measure, power over his legs and arms. On admission, his condition was as follows:--He could make a few uncertain and staggering steps, his knees trembled, his arms shook, and if he attempted to grasp anything when he lay in bed, there were involuntary twitchings of groups of muscles. There was no pain; the sensibility of the skin was unchanged; he had formication in the left arm; the spine was neither sensitive to pressure, nor unusually sensitive to heat (as, e.g., to the application of a hot sponge); the organs of special sense were not affected, but his speech was somewhat thick. He lived to 1845 in the same condition, but the paralysis became worse. There does not seem to have been any autopsy.

The effects of phosphorus vapour may be still further elucidated by one of Eulenberg’s[290] experiments on a rabbit. The vapour of burning phosphorus, mixed with much air, was admitted into a wooden hutch in which a strong rabbit sat. After 5 mgrms. of phosphorus had been in this manner consumed, the only symptoms in half an hour were salivation, and quickened and somewhat laboured respiration. After twenty-four hours had elapsed there was sudden indisposition, the animal fell as if lifeless, with the hind extremities stretched out, and intestinal movements were visible; there was also expulsion of the urine. These epileptiform seizures seem to have continued more or less for twelve days, and then ceased. After fourteen days the experiment was repeated on the same rabbit. The animal remained exposed to the vapour for three-quarters of an hour, when the epilepsy showed itself as before, and, indeed, almost regularly after feeding. Between the attacks the respiration was slowed. Eight weeks afterwards there was an intense icterus, which disappeared at the end of ten weeks.

[290] Gewerbe Hygiene, p. 255.

§ 287. =Chronic phosphorus poisoning= has frequently been noticed in persons engaged either in the manufacture of phosphorus or in its technical application. Some have held that the symptoms are due to an oxidation product of phosphorus rather than to phosphorus itself; but in one of Eulenberg’s experiments, in which a dove was killed by breathing phosphorus fumes evolved by phosphorus oil, phosphorus was chemically recognised in the free state in the lungs. The most constant and peculiar effect of breathing small quantities of phosphorus vapour is a necrosis of the lower jaw. There is first inflammation of the periosteum of the jaw, which proceeds to suppuration and necrosis of a greater or smaller portion. The effects may develop with great suddenness, and end fatally. Thus Fournier and Olliver[291] relate the case of a girl, fourteen years old, who, after working four years in a phosphorus manufactory, was suddenly affected with periostitis of the upper jaw, and with intense anæmia. An eruption of purpuric spots ensued, and she died comatose. There is now little doubt, that minute doses of phosphorus have a specific action on the bones generally, and more especially on the bones of the jaw. Wegner[292] administered small daily doses to young animals, both in the state of vapour, and as a finely-divided solid. The condition of the bones was found to be more compact than normal, the medullary canals being smaller than in healthy bone, the ossification was quickened. The formation of callus in fractured limbs was also increased.

[291] Gaz. hebd. de Méd., 29, p. 461, 1868.

[292] Virchow’s Arch. f. path. Anat., lv. 11.

§ 288. =Changes in the Urinary Secretion.=--It has been before stated that, at a certain period of the illness, the renal secretion is scantier than in health, the urine diminishing, according to Lebert and Wyss’s[293] researches, to one-half on the third, fourth, or fifth day. It frequently contains albumen, blood, and casts. When jaundice is present, the urine has then all the characters noticed in icterus; leucin and tyrosin, always present in acute yellow atrophy of the liver, have been found in small quantity in jaundice through phosphorus; lactic acid is also present. The urea is much diminished, and, according to Schultzen and Riess,[294] may be towards death entirely absent. Lastly, it is said that there is an exhalation of either phosphorus vapour or phosphine from such urine. In some cases the urine is normal, e.g., in a case recorded by E. H. Starling, M.D., and F. G. Hopkins, B.Sc. (Guy’s Hospital Report, 1890), in which a girl, aged 18, died on the fifth day after taking phosphorus paste, the liver was fatty, and there was jaundice; but the urine contained neither leucin nor tyrosin, and was stated to be generally normal.

[293] Archiv Générale de Méd., 6 Sér., Tom. 12, 1868, p. 709.

[294] Annalen der Charité, Berlin.

§ 289. =Changes in the blood= during life have been several times observed. In a case attended by M. Romellære of Brussels,[295] in which a man took the paste from 300 matches, and under treatment by turpentine recovered, the blood was frequently examined, and the leucocytes found much increased in number. There is a curious conflict of evidence as to whether phosphorus prevents coagulation of the blood or not. Nasse asserted that phosphorated oil given to a dog fully prevented coagulation; P. I. Liebreck[296] also, in a series of researches, found the blood dark, fluid, and in perfect solution. These observations were also supported by V. Bibra and Schuchardt.[297] Nevertheless, Lebert and Wyss found the blood, whether in the veins or in extravasations, in a normal condition. Phosphorus increases the fatty contents of the blood. Ritter found that phosphorus mixed with starch, and given to a dog, raised the fatty content from the normal 2 per 1000 up to 3·41 and 3·47 per 1000. Eug. Menard[298] saw in the blood from the jugular and portal veins, as well as in extravasations, microscopic fat globules and fine needle-shaped crystals soluble in ether.

[295] Tardieu, op. cit., Case 31.

[296] Diss. de Venefico Phosphoreo Acuto, Upsal, 1845.

[297] V. Bibra u. Geist, Die Krankheiten der Arbeiter in den Phosphorzundholz Fabriken, 1847, S. 59, &c.; Henle u. v. Pfeuffer’s Zeitschr. f. ration. Med., N. F., Bd. 7, Hft. 3, 1857.

[298] Étude Expérimentale sur quelques lésions de l’Empoisonnement aigu par le Phosphore (Thèse), Strasbourg, 1869.

§ 290. =Antidote--Treatment.=--After emptying the stomach by means of emetics or by the stomach-pump, oil of turpentine in full medicinal doses, say 2·5 c.c. (about 40 min.), frequently administered, seems to act as a true antidote, and a large percentage of cases treated early in this way recover.

§ 291. =Poisonous Effects of Phosphine (phosphuretted hydrogen).=--Experiments on pigeons, on rats, and other animals, and a few very rare cases among men, have shown that phosphine has an exciting action on the respiratory mucous membranes, and a secondary action on the nervous system. Eulenberg[299] exposed a pigeon to an atmosphere containing 1·68 per cent. of phosphine. There was immediate unrest; at the end of three minutes, quickened and laboured breathing (100 a minute); after seven minutes, the bird lay prostrate, with shivering of the body and wide open beak; after eight minutes, there was vomiting; after nine minutes, slow breathing (34 per minute); after twelve minutes, convulsive movements of the wings; and after thirteen minutes, general convulsions and death.

[299] Gewerbe Hygiene, p. 273.

The membranes of the brain were found strongly injected, and there were extravasations. In the mucous membrane of the crop there was also an extravasation. The lungs externally and throughout were of a dirty brown-red colour; the entire heart was filled with coagulated blood, which was weakly acid in reaction.

In a second experiment with another pigeon, there was no striking symptom save that of increased frequency of respiration and loss of appetite; at the end of four days it was found dead. There was much congestion of the cerebral veins and vessels, the mucous membrane of the trachea and bronchi were weakly injected, and the first showed a thin, plastic, diphtheritic-like exudation.

Dr. Henderson’s[300] researches on rats may also be noticed here. He found that an atmosphere consisting entirely of phosphine killed rats within ten minutes, an atmosphere with 1 per cent. in half an hour. The symptoms observed were almost exactly similar to those noticed in the first experiment on the pigeon quoted above, and the post-mortem appearances were not dissimilar. With smaller quantities of the gas, the first symptom was increased frequency of the respiration; then the animals showed signs of suffering intense irritation of the skin, scratching and biting at it incessantly; afterwards they became drowsy, and assumed a very peculiar attitude, sitting down on all-fours, with the back bent forward, and the nose pushed backwards between the forepaws, so as to bring the forehead against the floor of the cage. When in this position, the rat presented the appearance of a curled-up hedgehog. Phosphine, when injected into the rectum, is also fatal; the animals exhale some of the gas from the lungs, and the breath, therefore, reduces solutions of silver nitrate.[301]

[300] Journ. Anat. and Physiol., vol. xiii. p. 19.

[301] Dybskowsky, Med. Chem. Untersuchungen aus Hoppe-Seyler’s Labor. in Tübingen, p. 57.

Brenner[302] has recorded the case of a man twenty-eight years old, a pharmaceutist, who is supposed to have suffered from illness caused by repeated inhalations of minute quantities of phosphine. He was engaged for two and a half years in the preparation of hypophosphites; his illness commenced with spots before the eyes, and inability to fix the attention. His teeth became very brittle, and healthy as well as carious broke off from very slight causes. Finally, a weakness of the arms and limbs developed in the course of nine months into complete locomotor ataxy.

[302] St. Petersburg Med. Zeitschr., 4 Hft., 1865.

§ 292. Blood takes up far more phosphine than water. Dybskowsky found that putting the coefficient of solubility of phosphine in pure water at ·1122 at 15°, the coefficient for venous blood was ·13, and for arterial 26·73; hence the richer the blood is in oxygen the more phosphine is absorbed. It seems probable that the poisonous gas reacts on the oxyhæmoglobin of the blood, and phosphorous acid is formed. This is supported by the fact that a watery extract of such blood reduces silver nitrate, and has been also found feebly acid. The dark blood obtained from animals poisoned by phosphine, when examined spectroscopically, has been found to exhibit a band in the violet.

§ 293. =Post-mortem Appearances.=--There are a few perfectly well authenticated cases showing that phosphorus may cause death, and yet no lesion be discovered afterwards. Thus, Tardieu[303] cites a case in which a woman, aged 45, poisoned herself with phosphorus, and died suddenly the seventh day afterwards. Dr. Mascarel examined the viscera with the greatest care, but could discover absolutely no abnormal conditions; the only symptoms during life were vomiting, and afterwards a little indigestion. It may, however, be remarked that the microscope does not seem to have been employed, and that probably a close examination of the heart would have revealed some alteration of its ultimate structure. The case quoted, by Taylor[304] may also be mentioned, in which a child was caught in the act of sucking phosphorus matches, and died ten days afterwards in convulsions. None of the ordinary post-mortem signs of poisoning by phosphorus were met with, but the intestines were reddened throughout, and there were no less than ten invaginations; but the case is altogether a doubtful one, and no phosphorus may actually have been taken. It is very difficult to give in a limited space anything like a full picture of the different lesions found after death from phosphorus, for they vary according as to whether the death is speedy or prolonged, whether the phosphorus has been taken as a finely-divided solid, or in the form of vapour, &c. It may, however, be shortly said, that the most common changes are fatty infiltration of the liver and kidneys, fatty degeneration of the heart, enlargement of the liver, ecchymoses in the serous membranes, in the muscular, in the fatty, and in the mucous tissues. When death occurs before jaundice supervenes, there may be little in the aspect of the corpse to raise a suspicion of poison; but if intense jaundice has existed during life, the yellow staining of the skin, and it may be, spots of purpura, will suggest to the experienced pathologist the possibility of phosphorus poisoning. In the mouth and throat there will seldom be anything abnormal. In one or two cases of rapid death among infants, some traces of the matches which had been sucked were found clinging to the gums. The stomach may be healthy, but the most common appearance is a swelling of the mucous membrane and superficial erosions. Virchow,[305] who was the first to call attention to this peculiar grey swelling of the intestinal mucous membrane under the name of gastritis glandularis or gastradenitis, shows that it is due to a fatty degeneration of the epithelial cells, and that it is by no means peculiar to phosphorus poisoning. The swelling may be seen in properly-prepared sections to have its essential seat in the glands of the mucous membrane; the glands are enlarged, their openings filled with large cells, and each single cell is finely granular. Little centres of hæmorrhage, often microscopically small, are seen, and may be the centres of small inflammations; their usual situation is on the summit of the rugæ. Very similar changes are witnessed after death from septicæmia, pyæmia, diphtheria, and other diseases. The softening of the stomach, gangrene, and deep erosions, recorded by the earlier authors, have not been observed of late years, and probably were due to post-mortem changes, and not to processes during life. The same changes are to be seen in the intestines, and there are numerous extravasations in the peritoneum.

[303] L’Empoisonnement, p. 520.

[304] Poisons, 3rd ed., p. 276.

[305] Virchow’s Archiv. f. path. Anat., Bd. 31, Hft. 3, 399.

The liver shows of all the organs the most characteristic signs; a more or less advanced fatty infiltration of its structure takes place, which was first described as caused by phosphorus by Hauff in 1860.[306] It is the most constant pathological evidence both in man and animal, and seems to occur at a very early period, Munk and Leyden having found a fatty degeneration in the liver far advanced in twenty-four hours[307] after poisoning. In rats and mice poisoned with paste, I have found this evident to the naked eye twelve hours after the fatal dose. The liver is mostly large, but in a case[308] recorded in the Lancet, July 14, 1888, the liver was shrunken; it has a pale yellow (or sometimes an intense yellow) colour; on section the cut surface presents a mottled appearance; the serous envelopes, especially along the course of the vessels, exhibit extravasations of blood. The liver itself is more deficient in blood than in the normal condition, and the more bloodless it is, the greater the fatty infiltration.

[306] Hauff collected 12 cases, and found a fatty liver in 11.--Würtemb. Med. Corresp. Bl., 1860, No. 34.

[307] Die acute Phosphor-Vergiftung, Berlin, 1865.

[308] This case, from the similarity of the pathological appearances to those produced by yellow atrophy, deserves fuller notice:--“Frances A. Cowley, aged 20, on her own admission, took some rat paste on Tuesday, June 19th. Death ensued eleven days later. The initial symptoms were not very marked. Nausea and vomiting continued with moderate severity for a few days and then ceased. There ensued a feeling of depression. Towards the end insensibility, icterus, and somewhat profuse metrorrhagia supervened. At the necropsy the skin and conjunctivæ were observed of a bright yellow colour. There was no organic disease save of a recent nature, and entirely attributable to the action of the poison ingested. The stomach contained about three-quarters of a pint of dark claret-coloured fluid, consisting largely of blood derived from capillary hæmorrhage from the mucous membrane. There was no solution of continuity of the mucous membrane, which showed traces of recent irritation. The whole surface presented a yellow icteric tint, except the summits of some of the rugæ, which were of a bright pink colour. There was also faint wrinkling of the mucous membrane. The upper part of the small intestine was affected in much the same manner as the stomach. The large intestine contained a quantity of almost colourless fæces. The liver was shrunken, weighing only 26 ozs., and both on its outer and sectional surface exactly resembled the appearances produced by acute yellow atrophy, except that there were greater congestion and interstitial hæmorrhage in patches. The lobules of the liver were in many places unrecognisable; in others they stood in bold relief as brilliant canary-yellow patches, standing in strong contrast to the deep dark-red areas of congestion and extravasation. The gall-bladder contained about 2 drachms of thin greyish fluid, apparently all but devoid of bile. The urinary bladder was empty; the kidneys were enlarged; the cortex was very pale and bile-stained, of greater depth than natural, and of softer consistence. The spleen was not enlarged, nor was it in the least degree softened. In addition to the bleeding from the uterus noticed during life, there was capillary hæmorrhage into the right lung and pleura, into the pericardium, and, as already mentioned, into the stomach. The brain was healthy.”

In the Museum of the Royal College of Surgeons there is a preparation (No. 2737) of the section of a liver derived from a case of phosphorus poisoning.

A girl, aged 18, after two days’ illness, was admitted into Guy’s Hospital. She confessed to having eaten a piece of bread coated with phosphorus paste. She had great abdominal pain, and died on the seventh day after taking the phosphorus. A few hours before her death she was profoundly and suddenly collapsed. The liver weighed 66 ozs. The outlines of the hepatic lobules were very distinct, each central vein being surrounded by an opaque yellowish zone; when fresh the hue was more uniform, and the section was yellowish-white in colour. A microscopical examination of the hepatic cells showed them laden with fat globules, especially in the central parts of the liver.

The microscopic appearances are also characteristic. In a case of suicidal poisoning by phosphorus, in which death took place on the seventh day, the liver was very carefully examined by Dr. G. F. Goodart, who reported as follows:--

“Under a low power the structure of the liver is still readily recognisable, and in this the specimen differs from slides of three cases of acute yellow atrophy that I have in my possession. The hepatic cells are present in large numbers, and have their natural trabecular arrangement. The columns are abnormally separated by dilated blood or lymph-spaces, and the individual cells are cloudy and ill-defined. The portal channels are everywhere characterised by a crowd of small nuclei which stain with logwood deeply. The epithelium of the smaller ducts is cloudy, and blocks the tubes in many cases. Under a high power (one-fifth) it is seen that the hepatic cells are exceedingly ill-defined in outline, and full of granules and even drops of oil. But in many parts, even where the cells themselves are hazy, the nucleus is still fairly visible. It appears to me that, in opposition to what others have described, the nuclei of the cells have in great measure resisted the degenerative process. The change in the cells is uniform throughout each lobule, but some lobules are rather more affected than others. The blood-spaces between the cells are empty, and the liver appears to be very bloodless. The portal canals are uniformly studded with small round nuclei or cells, which are in part, and might be said in great part, due to increase of the connective tissue or to a cirrhotic process. But I am more disposed to favour the view that they are due to migration from the blood-vessels, because they are so uniform in size, and the hepatic cells and connective tissue in their neighbourhood are undergoing no changes in the way of growth whatever. I cannot detect any fatty changes in the vessels, but some of the smaller biliary ducts contain some cloudy albuminous material, and their nucleation is not distinct. No retained biliary pigment is visible.”[309]

[309] “A Recent Case of Suicide,” by Herbert J. Capon, M.D.--Lancet, March 18, 1882.

Oscar Wyss,[310] in the case of a woman twenty-three years old, who died on the fifth day after taking phosphorus, describes, in addition to the fatty appearance of the cells, a new formation of cells lying between the lobules and in part surrounding the gall-ducts and the branches of the portal vein and hepatic artery.

[310] Virchow’s Archiv. f. path. Anat., Bd. 33, Hft. 3, S. 432, 1865.

Salkowsky[311] found in animals, which he killed a few hours after administering to them toxic doses of phosphorus, notable hyperæmia of the throat, intestine, liver, and kidneys--both the latter organs being larger than usual. The liver cells were swollen, and the nuclei very evident, but they contained no fat, fatty drops being formed afterwards.

[311] Ibid., Bd. 34, Hft. 1 u. 2, S. 73, 1865.

§ 294. =The kidneys= exhibit alterations very similar and analogous to those of the liver. They are mostly enlarged, congested, and flabby, with extravasations under the capsule, and show microscopic changes essentially consisting in a fatty degeneration of the epithelium. In cases attended with hæmorrhage, the tubuli may be here and there filled with blood. The fatty epithelium is especially seen in the contorted tubes, and the walls of the vessels, both of the capsule and of the malpighian bodies, also undergo the same fatty change. In cases in which death has occurred rapidly, the kidneys have been found almost healthy, or a little congested only. The pancreas has also been found with its structure in part replaced by fatty elements.

Of great significance are also the fatty changes in the general muscular system, and more especially in the heart. The muscular fibres of the heart quickly lose their transverse striæ, which are replaced by drops of fat. Probably this change is the cause of the sudden death not unfrequently met with in phosphorus poisoning.

=In the lungs=, when the phosphorus is taken in substance, there is little “naked-eye” change, but Perls,[312] by manometric researches, has shown that the elasticity is always decreased. According to experiments on animals, when the vapour is breathed, the mucous membrane is red, congested, swollen, and has an acid reaction.

[312] Deutsch. Archiv f. klin. Med., vi. Hft. 1, S. 1, 1869.

=In the nervous system= no change has been remarked, save occasionally hæmorrhagic points and extravasations.

§ 295. =Diagnostic Differences between Acute Yellow Atrophy of the Liver and Fatty Liver produced by Phosphorus.=--O. Schultzen and O. L. Riess have collected and compared ten cases of fatty liver from phosphorus poisoning, and four cases of acute yellow atrophy of the liver, and, according to them, the chief points of distinction are as follows:--In phosphorus poisoning the liver is large, doughy, equally yellow, and with the acini well marked; while in acute yellow atrophy the liver is diminished in size, tough, leathery, and of a dirty yellow hue, the acini not being well mapped out. The “phosphorus” liver, again, presents the cells filled with large fat drops, or entirely replaced by them; but in the “atrophy” liver, the cells are replaced by a finely-nucleated detritus and through newly-formed cellular tissue. Yellow atrophy seems to be essentially an inflammation of the intralobular connective tissue, while in phosphorus poisoning the cells become gorged by an infiltration of fat, which presses upon the vessels and lessens the blood supply, and the liver, in consequence, may, after a time, waste.

There is also a clinical distinction during life, not only in the lessening bulk of the liver in yellow atrophy, in opposition to the increase of size in the large phosphorus liver, but also in the composition of the renal secretion. In yellow atrophy the urine contains so much leucine and tyrosin, that the simple addition of acetic acid causes at once a precipitate. Schultzen and Riess also found in the urine, in cases of yellow atrophy, oxymandelic acid (C₈H₈O₄), but in cases of phosphorus poisoning a nitrogenised acid, fusing at 184° to 185°.

According to Maschka, grey-white, knotty, fæcal masses are found in the intestines in yellow atrophy, but never in cases of phosphorus poisoning. In the latter, it is more common to find a slight intestinal catarrh and fluid excreta.

§ 296. =The Detection of Phosphorus=.--The following are the chief methods in use for the separation and detection of phosphorus:[313]--

[313] It has been recommended to dissolve the phosphorus out from organic matters by carbon disulphide. On evaporation of the latter the phosphorus is recognised by its physical properties. Such a method is of but limited application, although it may sometimes be found useful. I have successfully employed it in the extraction of phosphorus from the crop of a fowl; but on this occasion it happened to be present in large quantity.

1. =Mitscherlich’s Process=.--The essential feature of this process is simply distillation of free phosphorus, and observation of its luminous properties as the vapour condenses in the condensing tube. The conditions necessary for success are--(1) that the apparatus should be in total darkness;[314] and (2) that there should be no substance present, such as alcohol or ammonia,[315] which, distilling over with the phosphorus-vapour, could destroy its luminosity. A convenient apparatus, and one certain to be in all laboratories, is an ordinary Florence flask, containing the liquid to be tested, fitted to a glass Liebig’s condenser, supported on an iron sand-bath (which may, or may not, have a thin layer of sand), and heated by a Fletcher’s low temperature burner. The distillate is received into a flask. This apparatus, if in darkness, works well; but should the observer wish to work in daylight, the condenser must be enclosed in a box perfectly impervious to light, and having a hole through which the luminosity of the tube may be seen, the head of the operator and the box being covered with a cloth. If there be a stream of water passing continuously through the condenser, a beautiful luminous ring of light appears in the upper part of the tube, where it remains fixed for some time. Should, however, the refrigeration be imperfect, the luminosity travels slowly down the tube into the receiver. In any case, the delicacy of the test is extraordinary.[316] If the organic liquid is alkaline, or even neutral, there will certainly be some evolution of ammonia, which will distil over before the phosphorus, and retard (or, if in sufficient quantity, destroy) the luminosity. In such a case it is well, as a precaution, to add enough sulphuric acid to fix the ammonia, omitting such addition if the liquid to be operated upon is acid.

[314] Any considerable amount of phosphorescence can, however, be observed in twilight.

[315] Many volatile substances destroy the luminous appearance of phosphorus vapour, e.g., chlorine, hydric sulphide, sulphur dioxide, carbon disulphide, ether, alcohol, petroleum, turpentine, creasote, and most essential oils. On the other hand, bromine, hydrochloric acid, camphor, and carbonate of ammonia do not seem to interfere much with the phosphorescence.

[316] Fresenius states that he and Neubauer, with 1 mgrm. of phosphorus in 200,000, recognised the light, which lasted for half an hour.--Zeitschr. f. anal. Chem., i. p. 336.

2. =The Production of Phosphine= (PH₃).--Any method which produces phosphine (phosphuretted hydrogen), enabling that gas to be passed through nitrate of silver solution, may be used for the detection of phosphorus. Thus, Sonnenschein states that he has found phosphorus in extraordinary small amount, mixed with various substances, by heating with potash in a flask, and passing the phosphine into silver nitrate, separating the excess of silver, and recognising the phosphoric acid by the addition of molybdate of ammonia.[317]

[317] Sonnenschein, Handbuch der gerichtlichen Chemie, Berlin, 1869.

The usual way is, however, to produce phosphine by means of the action on free phosphorus of nascent hydrogen evolved on dissolving metallic zinc in dilute sulphuric acid. Phosphine is formed by the action of nascent hydrogen on solid phosphorus, phosphorous acid, and hypophosphorous acid; but no phosphine can be formed in this way by the action of hydrogen on phosphoric acid.

Since it may happen that no free phosphorus is present, but yet the first product (phosphorous acid) of its oxidation, the production of phosphine becomes a necessary test to make on failure of Mitscherlich’s test; if no result follows the proper application of the two processes, the probability is that phosphorus has not been taken.

Blondlot and Dusart evolve hydrogen from zinc and dilute sulphuric acid, and pass the gas into silver nitrate; if the gas is pure, there is of course no reduction; the liquid to be tested is then added to the hydrogen-generating liquid, and if phosphorous or hypophosphorous acids be present, a black precipitate of phosphor-silver will be produced. To prove that this black precipitate is neither that produced by SH₂, nor by antimony nor arsenic, the precipitate is collected and placed in the apparatus to be presently described, and the spectroscopic appearances of the phosphine flame observed.

3. =Tests Dependent on the Combustion of Phosphine= (PH₃).--A hydrogen flame, containing only a minute trace of phosphorus, or of the lower products of its oxidation, acquires a beautiful green tint, and possesses a characteristic spectrum. In order to obtain the latter in its best form, the amount of phosphine must not be too large, or the flame will become whitish and livid, and the bands lose their defined character, rendering the spectrum continuous. Again, the orifice of the tube whence the gas escapes must not be too small; and the best result is obtained when the flame is cooled.

M. Salet has proposed two excellent methods for the observation of phosphine by the spectroscope:--

(1) He projects the phosphorus-flame on a plane vertical surface, maintained constantly cold by means of a thin layer of running water; the green colour is especially produced in the neighbourhood of the cool surface.

(2) At the level of the base of the flame, there is an annular space, through which a stream of cold air is continually blown upwards. Thus cooled, the light is very pronounced, and the band δ, which is almost invisible in the ordinary method of examination, is plainly seen.[318]

[318] Consult Spectres Lumineux, par M. Lecoq de Boisbaudran, Paris, 1874. See also Christofle and Beilstrom’s “Abhandlung,” in _Fresenius’ Zeitschr. f. anal. Chem._, B. 2, p. 465, and B. 3, p. 147.

An apparatus (devised by Blondlot, and improved by Fresenius) for the production of the phosphine flame in medico-legal research, is represented in the following diagram:--

Several of the details of this apparatus may be modified at the convenience of the operator. A is a vessel containing sulphuric acid; B is partly filled with granulated zinc, and hydrogen may be developed at pleasure; c contains a solution of nitrate of silver; d is a tube at which the gas can be lit; e, a flask containing the fluid to be tested, and provided with a tube f, at which also the gas issuing can be ignited. The orifice should be provided with a platinum nozzle. When the hydrogen has displaced the air, both tubes are lit, and the two flames, being side by side, can be compared. Should any phosphorus come over from the zinc (a possibility which the interposed silver nitrate ought to guard against), it is detected; the last flask is now gently warmed, and if the flame is green, or, indeed, in any case, it should be examined by the spectroscope.[319]

[319] F. Selmi has proposed the simple dipping of a platinum loop into a liquid containing phosphoric acid, and then inserting it into the tip of a hydrogen flame.

§ 297. The spectrum, when fully developed, shows one band in the orange and yellow between C and D, but very close to D, and several bands in the green. But the bands δ, γ, α, and β are the most characteristic. The band δ has its centre about the wave-length 599·4; it is easily distinguished when the slit of the spectroscope is a little wide, but may be invisible if the slit is too narrow. It is best seen by M. Salet’s second process, and, when cooled by a brisk current of air, it broadens, and may extend closer to D. The band γ has a somewhat decided border towards E, while it is nebulous towards D, and it is, therefore, very difficult to say where it begins or where it ends; its centre may, however, be put at very near 109 of Boisbaudran’s scale, corresponding to W. L. 560·5, if the flame is free. This band is more distinct than β, but with a strong current of air the reverse is the case. The middle of the important band α is nearly marked by Fraunhofer’s line E. Boisbaudran gives it as coinciding with 122 of his scale W. L. 526·3. In ordinary conditions (that is, with a free uncooled flame) this is the brightest and most marked of all the bands. The approximate middle of the band β is W. L. 510·6 (Boisbaudran’s scale 129·00).

=Lipowitz’s Sulphur Test.=--Sulphur has the peculiar property of condensing phosphorus on its surface, and of this Lipowitz proposed to take advantage. Pieces of sulphur are digested some time with the liquid under research, subsequently removed, and slightly dried. When examined in the dark, should phosphorus be present, they gleam strongly if rubbed with the finger, and develop a phosphorus odour. The test is wanting in delicacy, nor can it well be made quantitative; it has, however, an advantage in certain cases, e.g., the detection of phosphorus in an alcoholic liquid.

Scherer’s test, as modified by Hager,[320] is a very delicate and almost decisive test. The substances to be examined are placed in a flask with a little lead acetate (to prevent the possibility of any hydric sulphide being evolved), some ether added, and a strip of filter-paper soaked in a solution of silver nitrate is then suspended in the flask; this is conveniently done by making a slit in the bottom of the cork, and in the slit securing the paper. The closed flask is placed in the dark, and if phosphorus is present, in a few minutes there is a black stain. It may be objected that arsine will cause a similar staining, but then arsine could hardly be developed under the circumstances given. It is scarcely necessary to observe that the paper must be wet.

[320] Pharm. Central-halle, 20, 353.

§ 298. =Chemical Examination of the Urine.=--It may be desirable, in any case of suspected phosphorus poisoning, to examine the renal secretion for leucin and tyrosin, &c. Leucin may be found as a deposit in the urine. Its general appearance is that of little oval or round discs, looking like drops of fat. It can be recognised by taking up one or more of these little bodies and placing them in the author’s subliming cell (see § 314). By careful heating it will sublime wholly on to the upper cover. On now adding a little nitric acid to the sublimed leucin, and drying, and then to the dried residue adding a droplet of a solution of sodium hydrate, leucin forms an oily drop. Tyrosin also may occur as a sediment of little heaps of fine needles. The best test for tyrosin is to dissolve in hot water, and then add a drop of a solution of mercuric nitrate and mercurous nitrate, when a rose colour is at once developed, if the tyrosin is in very minute quantity; but if in more than traces, there is a distinct crimson precipitate. To separate leucin and tyrosin from the urine, the best process is as follows:--The urine is filtered from any deposit, evaporated to a thin syrup, and decanted from the second deposit that forms. The two deposits are mixed together and treated with dilute ammonia, which will dissolve out any tyrosin and leave it in needles, if the ammonia is spontaneously evaporated on a watch-glass. The urine is then diluted and treated with neutral and basic acetates of lead, filtered, and the lead thrown out of the filtrate by hydric sulphide. The filtrate is evaporated to a syrup, and it then deposits leucin mixed with some tyrosin. If, however, the syrup refuses to crystallise, it is treated with cold absolute alcohol, and filtered, the residue is then boiled up with spirit of wine, which extracts leucin, and deposits it on cooling in a crystalline form. To obtain oxymandelic acid, the mother liquor, from which leucin and tyrosin have been extracted, is precipitated with absolute alcohol, filtered, and then the alcoholic solution evaporated to a syrup. This syrup is acidified by sulphuric acid, and extracted with ether; the ether is filtered off and evaporated to dryness; the dry residue will be in the form of oily drops and crystals. The crystals are collected, dissolved in water, and the solution precipitated by lead acetate to remove colouring-matters; after filtration it is finally precipitated by basic acetate. On decomposition of the basic acetate, by suspending in water and saturating with hydric sulphide, the ultimate filtrate on evaporation deposits colourless, flexible needles of oxymandelic acid. The nitrogenised acid which Schultzen and Riess obtained from urine in a case of phosphorus poisoning, was found in an alcohol and ether extract--warts of rhombic scales separating out of the syrupy residue. These scales gave no precipitate with basic acetate, but formed a compound with silver nitrate. The silver compound was in the form of shining white needles, and contained 33·9 per cent. of silver; the acid was decomposed by heat, and with lime yielded aniline. Its melting-point is given at from 184° to 185°. The occurrence of some volatile substance in phosphorus urine, which blackens nitrate of silver, and which is probably phosphine, was first noticed by Selmi.[321] Pesci and Stroppa have confirmed Selmi’s researches. It is even given off in the cold.

[321] Giornale Internaz. della Scienza Med., 1879, Nro. 5, p. 645.

§ 299. =The quantitative estimation of phosphorus= is best carried out by oxidising it into phosphoric acid, and estimating as ammon. magnesian phosphate. To effect this, the substances are distilled in an atmosphere of CO₂ into a flask with water, to which a tube containing silver nitrate is attached; the latter retains all phosphine, the former solid phosphorus. If necessary, the distillate may be again distilled into AgNO₃; and in any case the contents of the [U]-tube and flask are mixed, oxidised with nitromuriatic acid, filtered from silver chloride, and the phosphoric acid determined in the usual way.

In the case of a child poisoned by lucifer matches, Sonnenschein estimated the free phosphorus in the following way:--The contents of the stomach were diluted with water, a measured part filtered, and the phosphoric acid estimated. The other portion was then oxidised by HCl and potassic chlorate, and the phosphoric acid estimated--the difference being calculated as free phosphorus.

§ 300. =How long can Phosphorus be recognised after Death?=--One of the most important matters for consideration is the time after death in which free phosphorus, or free phosphoric acids, can be detected. Any phosphorus changed into ammon. mag. phosphate, or into any other salt, is for medico-legal purposes entirely lost, since the expert can only take cognisance of the substance either in a free state, as phosphine, or as a free acid.

The question, again, may be asked in court--Does the decomposition of animal substances rich in phosphorus develop phosphine? The answer to this is, that no such reaction has been observed.

A case is related[322] in which phosphorus was recognised, although the body had been buried for several weeks and then exhumed.

[322] Pharm. Zeitsch. f. Russl., Jahrg. 2, p. 87.

The expert of pharmacy of the Provincial Government Board of Breslau has also made some experiments in this direction, which are worthy of note:--Four guinea-pigs were poisoned, each by 0·023 grm. of phosphorus; they died in a few hours, and were buried in sandy-loam soil, 0·5 metre deep. Exhumation of the first took place four weeks after. The putrefying organs--heart, liver, spleen, stomach, and all the intestines--tested by Mitscherlich’s method of distillation, showed characteristic phosphorescence for nearly one hour.

The second animal was exhumed after eight weeks in a highly putrescent state. Its entrails, on distillation, showed the phosphorescent appearance for thirty-five minutes.

The third animal was taken from the earth after twelve weeks, but no free phosphorus could be detected, although there was evidence of the lower form of oxidation (PO₃) by Blondlot’s method.

The fourth animal was exhumed after fifteen weeks, but neither free phosphorus nor PO₃ could be detected.[323]

[323] Vierteljahrsschrift für gerichtliche Medicin, Jan. 7, 1876; see also Zeitschr. f. anal. Chemie, 1872.

A man, as well as a cat, was poisoned by phosphorus. On analysis, twenty-nine days after death, negative results were alone obtained.--Sonnenschein.

It will thus be evident that there is no constant rule, and that, even when decomposition is much advanced, an examination may be successful.

PART VI.--ALKALOIDS AND POISONOUS VEGETABLE PRINCIPLES SEPARATED FOR THE MOST PART BY ALCOHOLIC SOLVENTS.

DIVISION I.--VEGETABLE ALKALOIDS.

I.--General Methods of Testing and Extracting Alkaloids.

§ 301. =General Tests for Alkaloids.=--In order to ascertain whether an alkaloid is present or not, a method of extraction must be pursued which, while disposing of fatty matters, salts, &c., shall dissolve as little as possible of foreign substances--such a method, e.g., as the original process of Stas, or one of its modern modifications.

If to the acid aqueous solution finally obtained by this method a dilute solution of soda be added, drop by drop, until it is rendered feebly alkaline, and no precipitate appear, whatever other poisonous plant-constituents may be present, all ordinary alkaloids[324] are absent.

[324] In the case of morphine tartrate, this test will not answer. See the article on Morphine.

In addition to this negative test, there are also a number of substances which give well-marked crystalline or amorphous precipitates with alkaloids.

§ 302. These may be called “group reagents.” The chief members of the group-reagents are--Iodine dissolved in hydriodic acid, iodine dissolved in potassic iodide solution, bromine dissolved in potassic bromide solution, hydrargo-potassic iodide, bismuth-potassic iodide, cadmic potassic iodide; the chlorides of gold, of platinum, and mercury; picric acid, gallic acid, tannin, chromate of potash, bichromate of potash, phospho-molybdic acid, phospho-tungstic acid, silico-tungstic acid, and Fröhde’s reagent. It will be useful to make a few general remarks on some of these reagents.

=Iodine in hydriodic acid= gives either crystalline or amorphous precipitates with nearly all alkaloids; the compound with morphine, for example, is in very definite needles; with dilute solutions of atropine, the precipitate is in the form of minute dots, but the majority of the precipitates are amorphous, and all are more or less coloured.

=Iodine dissolved in a solution of potassic iodide= gives with alkaloids a reddish or red-brown precipitate, and this in perhaps a greater dilution than almost any reagent. When added to an aqueous solution, the precipitates are amorphous, but if added to an alcoholic solution, certain alkaloids then form crystalline precipitates; this, for example, is the case with berberine and narceine. By treating the precipitate with aqueous sulphurous acid, a sulphate of the alkaloid is formed and hydriodic acid, so that by suitable operations the alkaloid may readily be recovered from this compound. A solution of bromine in potassic bromide solution also gives similar precipitates to the above, but it forms insoluble compounds with phenol, orcin, and other substances.

=Mercuric potassic iodide= is prepared by decomposing mercuric chloride with potassic iodide in excess. The proportions are 13·546 grms. of mercuric chloride and 49·8 of potassic iodide, and water sufficient to measure, when dissolved, 1 litre. The precipitates from this reagent are white and flocculent; many of them become, on standing, crystalline.

=Bismuthic potassic iodide= in solution precipitates alkaloids, and the compounds formed are of great insolubility, but it also forms compounds with the various albuminoid bodies.

=Chloride of gold= forms with the alkaloids compounds, many of which are crystalline, and most admit of utilisation for quantitative determinations. Chloride of gold does not precipitate amides or ammonium compounds, and on this account its value is great. The precipitates are yellow, and after a while are partly decomposed, when the colour is of a reddish-brown.

=Platinic chloride= also forms precipitates with most of the alkaloids, but since it also precipitates ammonia and potassic salts, it is inferior to gold chloride in utility.

§ 303. (1.) =Phosphomolybdic Acid as a Reagent for Alkaloids.=--Preparation; Molybdate of ammonia is precipitated by phosphate of soda; and the well-washed yellow precipitate is suspended in water and warmed with carbonate of soda, until it is entirely dissolved. This solution is evaporated to dryness, and the ammonia fully expelled by heating. If the molybdic acid is fairly reduced by this means, it is to be moistened by nitric acid, and the heating repeated. The now dry residue is warmed with water, nitric acid added to strong acid reaction, and the mixture diluted with water, so that 10 parts of the solution contain 1 of the dry salt. The precipitates of the alkaloids are as follows:--

Aniline, Bright-yellow, flocculent. Morphine, „ „ Narcotine, Brownish-yellow, „ Quinine, Whitish-yellow, „ Cinchonine, „ „ Codeine, Brownish-yellow, voluminous. Strychnine, White-yellow, „ Brucine, Yelk-yellow, flocculent. Veratrine, Bright-yellow, „ Jervine, „ „ Aconitine, „ „ Emetine, „ „ Theine, Bright-yellow, voluminous. Theobromine, „ „ Solanine, Citron-yellow, pulverulent. Atropine, Bright-yellow, flocculent. Hyoscyamine, „ „ Colchicine, Orange-yellow, „ Delphinine, Grey-yellow, voluminous. Berberine, Dirty-yellow, flocculent. Coniine, Bright-yellow, voluminous. Nicotine, „ „ Piperine, Brownish-yellow, flocculent.

(2.) =Silico-Tungstic Acid as a Reagent for Alkaloids.=--Sodium tungstate is boiled with freshly precipitated gelatinous silica. To the solution is added mercurous nitrate, which precipitates the yellow mercurous silico-tungstate. This is filtered, well-washed, and decomposed by an equivalent quantity of hydrochloric acid; silico-tungstic acid then goes into solution, and mercurous chloride (calomel) remains behind. The clear filtrate is evaporated to drive off the excess of hydrochloric acid, and furnishes, on spontaneous evaporation, large, shining, colourless octahedra of silico-tungstic acid, which effloresce in the air, melt at 36°, and are easily soluble in water or alcohol.

This agent produces no insoluble precipitate with any metallic salt. Cæsium and rubidium salts, even in dilute solutions, are precipitated by it; neutral solutions of ammonium chloride give with it a white precipitate, soluble with difficulty in large quantities of water. It precipitates solutions of the salts of quinine, cinchonine, morphine, atropine, &c.; if in extremely dilute solution, an opalescence only is produced: for instance, it has been observed that cinchonine hydrochlorate in 1/200000, quinia hydrochlorate in 1/20000, morphia hydrochlorate in 1/15285 dilution, all gave a distinct opalescence.--Archiv der Pharm., Nov., Dr. Richard Godeffroy.

(3.) =Scheibler’s Method for Alkaloids: Phospho-Tungstic Acid.=--Ordinary commercial sodium tungstate is digested with half its weight of phosphoric acid, specific gravity 1·13, and the whole allowed to stand for some days, when the acid separates in crystals. A solution of these crystals will give a distinct precipitate with the most minute quantities of alkaloids, 1/200000 of strychnine, and 1/100000 of quinine. The alkaloid is liberated by digestion with barium hydrate (or calcium hydrate); and if volatile, may be distilled off, if fixed, dissolved out by chloroform. In complex mixtures, colouring-matter may be removed by plumbic acetate, the lead thrown out by SH₂, and concentrated, so as to remove the excess of SH₂.

§ 304. =Schulze’s reagent= is phospho-antimonic acid. It is prepared by dropping a strong solution of antimony trichloride into a saturated solution of sodic phosphate. The precipitation of the alkaloids is effected by this reagent in a sulphuric acid solution.

§ 305. =Dragendorff’s reagent= is a solution of potass-bismuth iodide; it is prepared by dissolving bismuth iodide in a hot solution of potassium iodide, and then diluting with an equal volume of iodide of potassium solution. On the addition of an acid solution of an alkaloid, a kermes-red precipitate falls down, which is in many cases crystalline.

=Marm’s reagent= is a solution of potass-cadmium iodide. It is made on similar principles.

=Potass-zinc iodide= in solution is also made similarly. The precipitates produced in solutions of narceine and codeine are crystalline and very characteristic.

§ 306. =Colour Tests.=--=Fröhde’s reagent= is made by dissolving 1 part of sodic molybdate in 10 parts of strong sulphuric acid; it strikes distinctive colours with many alkaloids.

=Mandelin’s reagent= is a solution of meta-vanadate of ammonia in mono- or dihydrated sulphuric acid. The strength should be 1 part of the salt to 200 of the acid. This reagent strikes a colour with many alkaloids, and aids to their identification. It is specially useful to supplement and correct other tests. The following table gives the chief colour reactions, with the alkaloids. (See also p. 55 for the spectroscopic appearances of certain of the colour tests.)

METHODS OF SEPARATION.

§ 307. =Stas’s Process.=--The original method of Stas[325] (afterwards modified by Otto)[326] consisted in extraction of the organic matters by strong alcohol, with the addition of tartaric acid; the filtered solution was then carefully neutralised with soda, and shaken up with ether, the ethereal solution being separated by a pipette. Subsequent chemists proposed chloroform instead of ether,[327] the additional use of amyl-alcohol,[328] and the substitution of acetic, hydrochloric, and sulphuric for tartaric acid.

[325] Annal d. Chem. u. Pharm., 84, 379.

[326] Ib., 100, 44. Anleitung zur Ausmittel. d. Gifte.

[327] Rodgers and Girwood, Pharm. Journ. and Trans., xvi. 497; Prollin’s Chem. Centralb., 1857, 231; Thomas, _Zeitschr. für analyt. Chem._, i. 517, &c.

[328] Erdmann and v. Ushlar, Ann. Chem. Pharm., cxx. pp. 121-360.

COLOUR REACTIONS[329] OF CERTAIN ALKALOIDS.

[329] Caustic potash also gives characteristic colours with certain alkaloids. Out of seventy-two alkaloids (using 0·5 mgrm.), the following alone gave characteristic colours when fused with KHO:--Quinine, grass-green, and peculiar odour; quinidine, becoming yellower and finally brown; cinchonine, at first brownish-red to violet, with green edges, later, bluish-green; cinchonidine, blue passing into grey; cocaine, greenish-yellow, turning to blue, and then dirty red on strong heating.--W. Lenz, Zeit. f. anal. Chem., 25, 29-32.

+-----------+-----------------+------------------+-------------------+ | Name of |Strong Sulphuric | Fröhde’s Reagent.|Mandelin’s Reagent.| |Substance. | Acid. | | | +-----------+-----------------+------------------+-------------------+ | | | | | |Strychnine.| ... | ... |Violet-blue, then | | | | |lastly cinnabar- | | | | |red. | | | | | | |Brucine. |Pale red. |Red, then yellow. |Yellow-red to | | | | |orange, afterwards | | | | |blood-red. | | | | | | |Curarine. |Fine red. | ... | ... | | | | | | |Quinine. | ... |Greenish. |Weak orange, then | | | | |blue-green, lastly | | | | |green-brown. | | | | | | |Atropine. | ... | ... |Red, then yellow- | | | | |red, and lastly | | | | |yellow. | | | | | | |Aconitine. | ... | ... | ... | | | | | | |Veratrine. |Yellow, then |Gamboge-yellow, |Yellow, orange, | | |orange, blood- |then cherry-red. |blood-red, lastly | | |red, lastly | |carmine-red. | | |carmine-red. | | | | | | | | |Morphine. | ... |Violet, green, |Reddish, then | | | |blue-green, and |blue-violet. | | | |yellow. | | | | | | | |Narcotine. |Yellow, then |Green, then brown-|Cinnabar-red, then | | |raspberry colour.|green, yellow, |carmine-red. | | | |lastly red. | | | | | | | |Codeine. | ... |Dirty green, then |Green-blue to blue.| | | |blue, lastly | | | | |yellow. | | | | | | | |Papaverine.| ... |Green, then blue- |Blue-green to blue.| | | |violet, lastly | | | | |cherry-red. | | | | | | | |Thebaine. |Blood-red, then |Orange, then |Red to orange. | | |yellow-red. |colourless. | | | | | | | |Narceine. |Grey-brown, then |Brown, green, red,|Violet, then | | |blood-red. |lastly blue. |orange. | | | | | | |Nicotine. | ... |Yellowish, then |Transitory dark | | | |red. |colour. | | | | | | |Coniine. | ... |Yellow. | ... | | | | | | |Colchicine.|Intense yellow. |Yellow to |Blue-green, then | | | |green-yellow. |brown. | | | | | | |Delphini- |Red. |Red-brown. |Red-brown to brown.| |dine. | | | | | | | | | |Solanine. |Red-yellow, then |Cherry-red, |Yellow-orange, | | |brown. |red-brown, yellow,|cherry-red, and | | | |yellow-green. |lastly violet. | +-----------+-----------------+------------------+-------------------+

§ 308. =Selmi’s Process for Separating Alkaloids.=--A method of separating alkaloids from an ethereal solution has been proposed by Selmi.[330] The alcoholic extract of the viscera, acidified and filtered, is evaporated at 65°; the residue taken up with water, filtered, and decolorised by basic acetate of lead. The lead is thrown out by sulphuretted hydrogen; the solution, after concentration, repeatedly extracted with ether; and the ethereal solution saturated with dry CO₂, which generally precipitates some of the alkaloids. The ethereal solution is then poured into clean vessels, and mixed with about half its volume of water, through which a current of CO₂ is passed for twenty minutes; this may cause the precipitation of other alkaloids not thrown down by dry CO₂. If the whole of the alkaloids are not obtained by these means, the solution is dehydrated by agitation with barium oxide, and a solution of tartaric acid in ether is added (care being taken to avoid excess); this throws down any alkaloid still present. The detection of any yet remaining in the viscera is effected by mixing with barium hydrate and a little water, and agitating with purified amylic alcohol; from the alcohol the alkaloids may be subsequently extracted by agitation with very dilute sulphuric acid.

[330] F. Selmi, Gazett. Chim. Ital., vj. 153-166, and Journ. Chem. Soc., i., 1877, 93.

Another ingenious method (also the suggestion of Selmi) is to treat the organic substance with alcohol, to which a little sulphuric acid has been added, to filter, digest with alcohol, and refilter. The filtrates are united, evaporated down to a smaller bulk, filtered, concentrated to a syrup, alkalised by barium hydrate, and, after the addition of freshly ignited barium oxide and some powdered glass, exhausted with dry ether; the ether filtered, the filtrate digested with lead hydrate; the ethereal solution filtered, evaporated to dryness, and finally again taken up with ether, which, this time, should leave on evaporation the alkaloid almost pure.

§ 309. =Dragendorff’s Process.=--To Dragendorff we owe an elaborate general method of separation, since it is applicable not only to alkaloids, but to glucosides, and other active principles derived from plants. His process is essentially a combination of those already known, and its distinctive features are the shaking up--(1) of the acid fluid with the solvent, thus removing colouring matters and certain non-alkaloidal principles; and (2) of the same fluid made alkaline. The following is his method in full. It may be advantageously used when the analyst has to search generally for vegetable poison, although it is, of course, far too elaborate for every case; and where, from any circumstance, there is good ground for suspecting the presence of one or two particular alkaloids or poisons, the process may be much shortened and modified.[331]

[331] Dragendorff’s Gerichtlich-chemische Ermittelung von Giften, St. Petersburg, 1876, p. 141.

I. The substance, in as finely-divided form as possible, is digested for a few hours in water acidified with sulphuric acid, at a temperature of 40° to 50°, and this operation is repeated two or three times, with filtering and pressing of the substances; later, the extracts are united. This treatment (if the temperature mentioned is not exceeded) does not decompose the majority of alkaloids or other active substances; but there are a few (e.g., solanine and colchicine) which would be altered by it; and, if such are suspected, maceration at the common temperature is necessary, with substitution of acetic for sulphuric acid.[332]

[332] When blood is to be examined, it is better to dry it, and then powder and extract with water acidified with dilute sulphuric acid. However, if the so-called volatile alkaloids are suspected, this modification is to be omitted.

II. The extract is next evaporated until it begins to be of a syrupy consistence; the residue mixed with three to four times its volume of alcohol, macerated for twenty-four hours at about 34°, allowed to become quite cool, and filtered from the foreign matters which have separated. The residue is washed with alcohol of 70 per cent.

III. The filtrate is freed from alcohol by distillation, the watery residue poured into a capacious flask, diluted (if necessary) with water, and filtered. Acid as it is, it is extracted at the common temperature, with frequent shaking, by freshly-rectified petroleum ether; and, after the fluids have again separated, the petroleum ether is removed, carrying with it certain impurities (colouring matter, &c.), which are in this way advantageously displaced. By this operation ethereal oils, carbolic acid, picric acid, &c., which have not been distilled, besides piperin, may also be separated. The shaking up with petroleum ether is repeated several times (as long as anything remains to be dissolved), and the products are evaporated on several watch-glasses.

RESIDUE OF PETROLEUM ETHER FROM THE ACID SOLUTION.

1. IT IS CRYSTALLINE. 2. IT IS AMORPHOUS. 3. IT IS VOLATILE, with a powerful odour; _ethereal oil, carbolic acid, &c._

A. It is yellowish, A. It is fixed. and with difficulty volatilised.

α. The crystals are α. Concentrated sul- dissolved by concen- phuric acid dissolves trated sulphuric it immediately-- acid, with the pro- violet, and later duction of a clear greenish-blue. yellow colour, pass- Constituents of the ing into brown and black hellebore. greenish-brown. Piperin.

β. The solution in sulphuric acid β. It dissolves with a yellow remains yellow; potassic cyanide colour, changing into fallow- and caustic potash colour it, on brown. warming, blood-red. _Constituents of aconite plant Picric acid. and products of the decomposition of Aconitine._

B. IT IS COLOURLESS, LIQUEFIES B. IT IS WHITE, SHARP-TASTING, EASILY, AND SMELLS STRONGLY. AND REDDENS THE SKIN. Camphor and similar matters. Capsicin.

It may be expected that the substances mentioned under the heads 1, 2, and 3 will be, in general, fully obtained by degrees. This is not the case, however, as regards piperin and picric acid.

IV. The watery fluid is now similarly shaken up with benzene, and the benzene removed and evaporated. Should the evaporated residue show signs of an alkaloid (and especially of theine), the watery fluid is treated several times with a fresh mixture of benzene, till a little of the last-obtained benzene extraction leaves on evaporation no residue. The benzene extracts are now united, and washed by shaking with distilled water; again separated and filtered, the greater part of the benzene distilled from the filtrate, and the remainder of the fluid divided and evaporated on several watch-glasses.

The evaporated residue may contain theine, colchicine, cubebin, digitalin, cantharidin, colocynthin, elaterin, caryophylline, absinthin, cascarillin, populin, santonin, &c., and traces of veratrine, delphinine, physostigmine, and berberine.

A remnant of piperin and picric acid may remain from the previous treatment with petroleum ether.

THE BENZENE RESIDUE FROM THE ACID SOLUTION.

1. IT IS CRYSTALLINE. 2. IT IS AMORPHOUS.

A. WELL-FORMED, COLOURLESS A. COLOURLESS OR PALE YELLOW CRYSTALS. RESIDUE.

α. Sulphuric acid dissolves the α. Sulphuric acid dissolves it at hair-like crystals without change first yellow; the solution be- of colour; evaporation with chlo- coming later red. Fröhde’s re- rine water, and subsequent treat- agent does not colour it violet. ment with ammonia, gives a Elaterin. murexide reaction. Theine.

β. Sulphuric acid leaves the β. Sulphuric acid dissolves red; rhombic crystals uncoloured. The Fröhde’s reagent violet-red;[333] substance, taken up by oil, and tannic acid does not precipitate. applied to the skin, produces a Populin. blister. Cantharidin.

γ. Sulphuric acid leaves the γ. Sulphuric acid dissolves it scaly crystals at first un- with a red colour; Fröhde’s coloured, then slowly develops a reagent[334] a beautiful cherry- reddening. It does not blister. red; tannic acid precipitates a Warm alcoholic potash-lye colours yellowish-white. Colocynthin. it a transitory red. Santonin.

δ. Sulphuric acid colours the δ. Sulphuric acid colours it crystals almost black, whilst it gradually a beautiful red, whilst takes itself a beautiful red tannin does not precipitate. colour. Cubebin. Constituents of the Pimento.

B. CRYSTALS PALE TO CLEAR YELLOW. B. PURE YELLOW RESIDUE.

α. Piperin. α. Sulphuric acid dissolves it yellow; on the addition of nitric acid, this solution is green, quickly changing to blue and violet. Colchicine.

β. Picric Acid. β. Sulphuric acid dissolves with separation of a violet powder; caustic potash colours it red; sulphide of ammonia violet, and, by heating, indigo-blue. Chrysammic acid.

γ. Caustic potash dissolves it purple. Aloetin.

C. MOSTLY UNDEFINED COLOURLESS C. A GREENISH BITTER RESIDUE, CRYSTALS. which dissolves brown in concen- trated sulphuric acid; in Fröhde’s reagent, likewise, at first brown, then at the edge green, changing into blue-violet, and lastly violet. Constituents of wormwood, with absynthin, besides quassiin, menyanthin, ericolin, daphnin, cnicin, and others.

α. Sulphuric acid dissolves it green-brown; bromine colours this solution red; dilution with water again green. The substance renders the heart-action of a frog slower. Digitalin.

β. Sulphuric acid dissolves it orange, then brown, lastly red- violet. Nitric acid dissolves it yellow, and water separates as a jelly out of the latter solution. Sulphuric acid and bromine do not colour it red. Gratiolin.

γ. Sulphuric acid dissolves it red-brown. Bromine produces in this solution red-violet stripes. It does not act on frogs. Cascarillin.

D. GENERALLY UNDEFINED YELLOW CRYSTALLISATION.--Sulphuric acid dis- solves it olive-green. The alcoholic solution gives with potassic iodide a colourless and green crystalline precipitate. Berberin.

[333] Fröhde’s reagent is described at page 239.

[334] Fröhde’s reagent is described at page 239.

V. As a complete exhaustion of the watery solution is not yet attained by the benzene agency, another solvent is tried.

THE WATERY SOLUTION IS NOW EXTRACTED IN THE SAME WAY BY CHLOROFORM.

In chloroform the following substances are especially taken up:--Theobromine, narceine, papaverine, cinchonine, jervine, besides picrotoxin, syringin, digitalin, helleborin, convallamarin, saponin, senegin, smilacin. Lastly, portions of the bodies named in Process IV., which benzene failed to extract entirely, enter into solution, as well as traces of brucine, narcotine, physostigmine, veratrine, delphinine. The evaporation of the chloroform is conducted at the ordinary temperature in four or five watch-glasses.

THE CHLOROFORM RESIDUE FROM THE ACID SOLUTION.[335]

[335] Chloroform removes small portions of acetate of aconitine from acid solution, Dunstan and Umney, J. C. S., 1892, p. 338.

1. THE RESIDUE IS MORE OR LESS 2. THE RESIDUE IS AMORPHOUS. MARKEDLY CRYSTALLINE.

A. _It gives in the sulphuric A. In acetic acid solution it acid solution evidence of an renders the action of the frog’s alkaloid by its action towards heart slower, or produces local iodine and iodide of potassium. anæsthesia._

aa. It does not produce local anæsthesia.

α. Sulphuric acid dissolves it α. Sulphuric acid dissolves it without the production of colour, red-brown, bromine produces a and chlorine and ammonia give no beautiful purple colour, water murexide reaction. Cinchonine. changes it into green, hydro- chloric acid dissolves it greenish-brown. Digitalin.

β. Sulphuric acid dissolves it β. Sulphuric acid dissolves it without colour, chlorine and yellow, then brown-red; on ad- ammonia give, as with theine, a dition of water this solution be- murexide reaction. Theobromine. comes violet. Hydrochloric acid, on warming, dissolves it red. Convallamarin.

bb. It produces local anæsthe- sia.

α. Sulphuric acid dissolves it brown. The solution becomes, by extracting with water, violet, and can even be diluted with two volumes of water without losing its colour. Saponin.

β. Sulphuric acid dissolves it yellow. On diluting with water the same reaction occurs as in the previous case, but more feebly. Senegin.

γ. Sulphuric acid does not colour γ. Sulphuric acid dissolves in the cold; on warming, the brown, and the solution becomes solution becomes a blue violet. red by the addition of a little Papaverine. water. The action is very weak. Smilacin.

cc. Sulphuric acid dissolves it with the production of a dirty red, hydrochloric acid, in the cold, with that of a reddish- brown colour, and the last solu- tion becomes brown on boiling. Constituents of the hellebore, particularly Jervine.

δ. Sulphuric acid dissolves it in the cold with the production of a blue colour. Unknown impurities, many commercial samples of Papaverine.

ε. Sulphuric acid dissolves it at first grey-brown; the solution becomes in about twenty-four hours blood-red. Iodine water colours it blue. Narceine.

B. IT GIVES NO ALKALOID REACTION. B. Is inactive, and becomes blue by sulphuric acid; by Fröhde’s reagent[336] dark cherry-red. Hydrochloric acid dissolves it red. The solution becomes, by boiling, colourless. Syringin.

α. Sulphuric acid dissolves it with a beautiful yellow colour; mixed with nitre, then moistened with sulphuric acid, and lastly treated with concentrated soda- lye, it is coloured a brick-red. Picrotoxin.

β. Sulphuric acid dissolves it with the production of a splendid red colour. The substance renders the heart-action of a frog slower. Helleborin.

[336] Described at p. 239.

VI. THE WATERY FLUID IS NOW AGAIN SHAKEN UP WITH PETROLEUM ETHER,

in order to take up the rest of the chloroform, and the watery fluid is saturated with ammonia. The watery solution of aconitine and emetine is liable to undergo, through free ammonia, a partial decomposition; but, on the other hand, it is quite possible to obtain, with very small mixtures of the substances, satisfactory reactions, even out of ammoniacal solutions.

VII. THE AMMONIACAL WATERY FLUID WITH PETROLEUM ETHER.

In the earlier stages Dragendorff advises the shaking up with petroleum ether at about 40°, and the removal of the ether as quickly as possible whilst warm. This is with the intention of separating by this fluid strychnine, brucine, emetine, quinine, veratrine, &c. Finding, however, that a full extraction by petroleum ether is either difficult or not practicable, he prefers, as we have seen, to conclude the operation by other agents, coming back again upon the ether for certain special cases. Such are the volatile alkaloids; and here he recommends treatment of the fluid by cold petroleum ether, taking care not to hasten the removal of the latter. Strychnine and other fixed alkaloids are then only taken up in small quantities, and the greater portion remains for the later treatment of the watery fluid by benzene.

A portion of the petroleum ether, supposed to contain in solution volatile alkaloids, is evaporated in two watch-glasses; to the one, strong hydrochloric acid is added, the other being evaporated without this agent. On the evaporation of the petroleum ether, it is seen whether the first portion is crystalline or amorphous, or whether the second leaves behind a strongly-smelling fluid mass, which denotes a volatile alkaloid. If the residue in both glasses is without odour and fixed, the absence of volatile acids and the presence of fixed alkaloids, strychnine, emetine, veratrine, &c., are indicated.

THE PETROLEUM ETHER RESIDUE FROM AMMONIACAL SOLUTION.

1. IT IS FIXED AND 2. IT IS FIXED AND 3. IT IS FIXED AND CRYSTALLINE. AMORPHOUS. ODOROUS.

A. _The crystals are A. On adding to the volatilised with watch-glass a little difficulty. hydrochloric acid, crystals are left behind._

aa. Sulphuric acid aa. Its solution is dissolves it without not precipitated by colour. platin chloride.

α. Potassic chromate α. The purest sulphuric α. The crystals of the colours this solution acid dissolves it hydrochloric compound a transitory blue, almost without colour; act on polarised then red. sulphuric acid con- light; and are mostly Strychnine. taining nitric acid, needle-shaped and red quickly becoming columnar. Coniine orange. and Methyl-Coniine. Brucine.

β. Potassic chromate β. Sulphuric acid dis- β. The crystals are does not colour it solves it yellow, cubical or tetra- blue; with chlorine becoming deep red. hedral. _Alkaloid water and ammonia it Veratrine. from Capsicum._ gives a green colour. Quinine.

γ. Sulphuric acid dis- solves it brown-green; Fröhde’s reagent red, changing into green. Emetine.

bb. The solution of the hydrochlorate of the alkaloid is pre- cipitated by platin chloride. Sarracinin.

γ. Sulphuric acid B. The residue of the dissolves it yellow, hydrochlorate of the and the solution be- alkaloid is amor- comes gradually a phous, or, by further beautiful deep red. additions of HCl, Sabadilline. becomes crystalline.

δ. The crystals are easily volatilised. Coniine.

aa. Its diluted aqueous solution is precipitated by platin chloride.

α. The hydrochlorate salt, being quickly treated with Fröhde’s reagent, gives after about two minutes a violet solution which gradually fades. Lobeliin.

β. The hydrochlorate smells like nicotine, and becomes by Fröhde’s reagent yellow, and after twenty-four hours pale red. Nicotine.

γ. The hydrochlorate is without odour, the free base smells faintly like aniline. Sparteine.

bb. The substance is not precipitated from a diluted solu- tion by platin chloride.

α. Its petroleum ether solution pro- duces no turbidity with a solution of picric acid in petro- leum ether; but it leaves behind, when mixed with the above, crystals mostly of three-sided plates. Trimethylamine.

β. The petroleum ether solution gives, on evaporation, when treated similarly, moss-like crystals. The substance is made blue by chloride of lime, as well as by diluted sulphuric acid and bichromate of potash. Aniline.

γ. The alkaloid does not smell like methylamine, and is not coloured by chlo- ride of lime, sul- phuric acid, or chro- mate of potash. Volatile alkaloid of the Pimento.

VIII. THE AMMONIACAL SOLUTION IS SHAKEN UP WITH BENZENE.

In most cases petroleum ether, benzene, and chloroform are more easily separated from acid watery fluids than from ammoniacal, benzene and chloroform causing here a difficulty which has perhaps deterred many from using this method. Dragendorff, however, maintains that he has never examined a fluid in which he could not obtain a complete separation of the benzene and water. If the upper benzene layer is fully gelatinous and emulsive, the under layer of water is to be removed with a pipette as far as possible, and the benzene with a few drops of absolute alcohol and filtration. As a rule, the water goes through first alone, and by the time the greater part has run through, the jelly in the filter, by dint of stirring, has become separated from the benzene, and, finally, the jelly shrinks up to a minimum, and the clear benzene filters off. Dragendorff filters mostly into a burette, from which ultimately the benzene and the water are separated.

The principal alkaloids which are dissolved in benzene are--strychnine, methyl and ethyl strychnine, brucine, emetine, quinine, cinchonine, atropine, hyoscyamine, physostigmine, aconitine, nepalin, the alkaloid of the Aconitum lycoctonum, aconellin, napellin, delphinine, veratrine, sabatrin, sabadilline, codeine, thebaine, and narcotine.

THE BENZENE RESIDUE DERIVED FROM THE AMMONIACAL SOLUTION.

1. IT IS FOR THE MOST PART CRYS- 2. IT IS FOR THE MOST PART AMOR- TALLINE. PHOUS.

a. Sulphuric acid dissolves it a. Pure sulphuric acid dis- without colour, the solution solves it either whitish-red or being coloured neither on stand- yellowish. ing nor on the addition of nitric acid.

aa. It dilates the pupil of a cat.

α. Platin chloride does not pre- α. The solution becomes by nitric cipitate the aqueous solution. acid immediately red, then quickly The sulphuric acid solution gives, orange. Brucine. on warming, a peculiar smell. Atropine.

β. Platin chloride applied to the β. The solution becomes by little solution precipitates. and little brownish-red. The sub- Hyoscyamine. stance is coloured red by chlo- ride of lime solution, and it contracts the pupil. Physostigmine.

bb. It does not dilate the pupil.

α. The sulphuric acid solution becomes blue by chromate of potash.

αα. The substance applied to a frog produces tetanus. Strychnine.

ββ. It lowers the number of res- pirations in a frog. Ethyl and Methyl Strychnine.

β. Sulphuric acid and bichromate of potash do not colour it blue.

αα. The sulphuric acid watery so- lution is fluorescent, and be- comes green on the addition of chlorine water and ammonia. Quinine and Cinchonine.

(The last is more difficult to dissolve in petroleum ether than quinine.)

ββ. The solution is not fluores- cent. Cinchonine.

b. Sulphuric acid dissolves it b. Pure sulphuric acid dis- at first colourless; the solution solves it yellow, and the solu- takes on standing a rose or tion becomes later beautiful red violet-blue; on addition of (with delphinine, more quickly a nitric acid, a blood-red or brown darker cherry-red.) coloration.

α. A solution in diluted sulphuric α. The hydrochloric acid solution acid becomes, on heating, deep gradually becomes red on heating. blood-red, and, when cooled, violet, with nitric acid. The aqueous solution is precipitated by ammonia. Narcotine.

αα. The substance acts on a frog, causing, in large doses, tetanus. Veratrine.

ββ. It is almost without action on frogs. Sabatrin.

β. The solution in diluted sul- β. The hydrochloric acid solution phuric acid becomes, on heating, does not, on heating, become red. a beautiful blue. Excess of ammo- Delphinine. nia does not precipitate in a diluted watery solution. Codeine.

c. Sulphuric acid dissolves it c. Pure sulphuric acid dis- with the production of a yellow solves it yellow, and the solu- colour. tion becomes later red-brown, and gradually violet-red.

α. The solution remains yellow α. The substance even in small on standing. Acolyctin. doses paralyses frogs, and dilates the pupil of a cat’s eye. Ether dissolves it with diffi- culty. Nepalin.

β. It becomes beautifully red. β. It is easily soluble in ether, Sabadilline. its effects are not so marked, and it does not dilate the pupil. Aconitine.

γ. Its effects are still feeble; it does not dilate the pupil, and is with difficulty dissolved by ether. Napellin.

d. Sulphuric acid dissolves it d. Sulphuric acid dissolves it with an immediate deep red-brown with a dark green colour, and the colour. Thebaine. solution becomes, even after a few seconds, a beautiful blood- red. Alkaloidal substances out of the Aconitum lycoctonum.

e. Sulphuric acid dissolves it e. Sulphuric acid dissolves it immediately blue. Substances brown-green, and Fröhde’s reagent accompanying the Papaverins. red, becoming beautifully green. Emetine.

IX. SHAKING OF THE AMMONIACAL WATERY SOLUTION WITH CHLOROFORM.

This extracts the remainder of the cinchonine and papaverine, narceine, and a small portion of morphine, as well as an alkaloid from the celandine.

THE RESIDUE FROM THE CHLOROFORM.

aa. The solution, on warming, is only slightly coloured.

α. But, after it is again cooled, it strikes with nitric acid a violet-blue; chloride of iron mixed with the substance gives a blue colour; Fröhde’s reagent also dissolves it violet. Morphine.

β. It is not coloured by nitric acid; it is also indifferent to chloride of iron. Cinchonine.

bb. The solution becomes by warming violet-blue. Papaverine.

γ. Sulphuric acid dissolves it greenish-brown, and the solution becomes, on standing, blood-red. Narceine.

δ. Sulphuric acid dissolves it a violet-blue. Alkaloidal constituent of the Celandine.

X. SHAKING UP OF THE WATERY FLUID WITH AMYL ALCOHOL.

From this process, besides morphine and solanine, as well as salicin, the remnants of the convallamarin, saponin, senegin, and narceine are also to be expected.

THE AMYL ALCOHOL RESIDUE.

a. Sulphuric acid dissolves it without colour in the cold. Morphine (see above).

b. Sulphuric acid dissolves it with the production of a clear yellow-red and the solution becomes brownish. Iodine water colours it a deep brown. The alcoholic solution gelatinises. Solanine.

c. Sulphuric acid dissolves it green-brown, becoming red. Narceine (see above).

d. Sulphuric acid dissolves it yellow, then brown-red, becoming violet on dilution with water. Hydrochloric acid dissolves it, and it becomes red on warming. It stops the heart-action in the systole. Convallamarin.

e. Hydrochloric acid dissolves it for the most part without colour. Saponin.

f. As the foregoing, but acting more feebly. Senegin.

g. Sulphuric acid dissolves it immediately a pure red. On warming with sulphuric acid and bichromate of potash, a smell of salicylic acid is developed. Salicin.

XI. DRYING THE WATERY FLUID WITH THE ADDITION OF POWDERED GLASS, AND EXTRACTION OF THE FINELY-DIVIDED RESIDUE BY CHLOROFORM.

The residue of the first chloroform extract lessens the number of respirations of a frog; the residue of the second and third chloroform extract becomes, by sulphuric acid and bichromate of potash, blue, passing into a permanent red.

Another portion of this residue becomes red on warming with diluted sulphuric acid. Curarine.

SHORTER PROCESS FOR SEPARATING SOME OF THE ALKALOIDS.

§ 310. A shorter process, recommended conditionally by Dragendorff, for brucine, strychnine, quinine, cinchonine, and emetine, is as follows:--

The substance, if necessary, is finely divided, and treated with sulphuric acid (dilute) until it has a marked acid reaction. To every 100 c.c. of the pulp (which has been diluted with distilled water to admit of its being filtered later), at least 5 to 10 c.c. of diluted sulphuric acid (1 : 5) are added. It is digested at 50° for a few hours, filtered, and the residue treated again with 100 c.c. of water at 50°. This extract is, after a few hours, again filtered; both the filtrates are mixed and evaporated in the water-bath to almost the consistency of a thin syrup. The fluid, however, must not be concentrated too much, or fully evaporated to dryness. The residue is now placed in a flask, and treated with three to four times its volume of alcohol of 90 to 95 per cent.; the mixture is macerated for twenty-four hours, and then filtered. The filtrate is distilled alcohol-free, or nearly so, but a small amount of alcohol remaining is not objectionable. The watery fluid is diluted to about 50 c.c., and treated with pure benzene; the mixture is shaken, and after a little time the benzene removed--an operation which is repeated. After the removal the second time of the benzene, the watery fluid is made alkaline with ammonia, warmed to 40° or 50°, and the free alkaloid extracted by twice shaking it up with two different applications of benzene. On evaporation of the latter, if the alkaloid is not left pure, it can be dissolved in acid, precipitated by ammonia, and again extracted by benzene.

§ 311. =Scheibler’s Process=.--A method very different from those just described is one practised by Scheibler. This is to precipitate the phosphotungstate of the alkaloid, and then to liberate the latter by digesting the precipitate with either hydrate of barium or hydrate of calcium, dissolving it out by chloroform, or, if volatile, by simple distillation. The convenience of Scheibler’s process is great, and it admits of very general application. In complex mixtures, it will usually be found best to precede the addition of phosphotungstic acid[337] by that of acetate of lead, in order to remove colouring matter, &c.; the excess of lead must in its turn be thrown out by SH₂, and the excess of SH₂ be got rid of by evaporation. Phosphotungstic acid is a very delicate test for the alkaloids, giving a distinct precipitate with the most minute quantities (1/200000 of strychnine and 1/100000 of quinine). A very similar method is practised by Sonnenschein and others with the aid of phospho-molybdic acid. The details of Scheibler’s process are as follows:--

[337] The method of preparing this reagent is as follows:--Ordinary commercial sodium tungstate is treated with half its weight of phosphoric acid, specific gravity, 1·13, and then allowed to stand for some days. Phosphotungstic acid separates in crystals.

The organic mixture is repeatedly extracted by water strongly acidified with sulphuric acid; the extract is evaporated at 30° to the consistence of a thin syrup; then diluted with water, and, after several hours’ standing, filtered in a cool place. To the filtered fluid phosphotungstic acid is added in excess, the precipitate filtered, washed with water to which some phosphotungstic acid solution has been added, and, whilst still moist, rinsed into a flask. Caustic baryta or carbonate of potash is added to alkaline reaction, and after the flask has been connected with bulbs containing HCl, it is heated at first slowly, then more strongly. Ammonia and any volatile alkaloids are driven over into the acid, and are there fixed, and can be examined later by suitable methods. The residue in the flask is carefully evaporated to dryness (the excess of baryta having been precipitated by CO₂), and then extracted by strong alcohol. On evaporation of the alcohol, the alkaloid is generally sufficiently pure to be examined, or, if not so, it may be obtained pure by re-solution, &c.

The author has had considerable experience of Scheibler’s process, and has used it in precipitating various animal fluids, but has generally found the precipitate bulky and difficult to manage.

§ 312. =Grandval and Lajoux’s Method=.[338]--The alkaloids are precipitated from a solution slightly acidified by hydrochloric or sulphuric acid by a solution of hydrarg-potassium iodide. The precipitate is collected on a filter, washed and then transferred to a flask; drop by drop, a solution of sodium sulphide is added; after each addition the suspended precipitate is shaken and allowed to stand for a few minutes, and a drop of the liquid taken out and tested with lead acetate; directly a slight brown colour appears, sufficient sodic sulphide has been added. The liquid is now left for half-an-hour, with occasional shaking. Then sulphuric acid is added until it is just acid, and the liquid is filtered and the mercury sulphide well washed. In the filtrate will be the sulphate of any alkaloid in solution; this liquid is now made alkaline with soda carbonate and shaken up, as in Dragendorff’s process, with appropriate solvents; such, for example, as ether, or chloroform, or acetone, or amylic alcohol, according to the particular alkaloid the analyst is searching for, and the solvent finally separated and allowed to evaporate, when the alkaloid is found in the residue.

[338] “Dosage des alcaloides à l’aide de l’iodure double de mercure et de potassium,” par MM. A. Grandval et Henri Lajoux, Journ. de Pharmacie, 5 sér. t. xxviii. 152-156.

§ 313. =Identification of the Alkaloids=.--Having obtained, in one way or other, a crystalline or amorphous substance, supposed to be an alkaloid, or, at all events, an active vegetable principle, the next step is to identify it. If the tests given in Dragendorff’s process have been applied, the observer will have already gone a good way towards the identification of the substance; but it is, of course, dangerous to trust to one reaction.

In medico-legal researches there is seldom any considerable quantity of the material to work upon. Hence the greatest care must be taken from the commencement not to waste the substance in useless tests, but to study well at the outset what--by the method of extraction used, the microscopic appearance, the reaction to litmus paper, and the solubility in different menstrua--it is likely to be. However minute the quantity may be, it is essential to divide it into different parts, in order to apply a variety of tests; but as any attempt to do this on the solid substance will probably entail loss, the best way is to dissolve it in a watch-glass in half a c.c. of alcohol, ether, or other suitable solvent. Droplets of this solution are then placed on watch-glasses or slips of microscopic glass, and to these drops, by the aid of a glass rod, different reagents can be applied, and the changes watched under the microscope as the drops slowly evaporate.

§ 314. =Sublimation of the Alkaloids.=--A very beautiful and elegant aid to the identification of alkaloids, and vegetable principles generally, is their behaviour towards heat.

Alkaloids, glucosides, the organic acids, &c., when carefully heated, either--(1) sublime wholly without decomposition (like theine, cytisin, and others); or (2) partially sublime with decomposition; or (3) are changed into new bodies (as, for example, gallic acid); or (4) melt and then char; or (5) simply char and burn away.

Many of these phenomena are striking and characteristic, taking place at different temperatures, subliming in characteristic forms, or leaving characteristic residues.

One of the first to employ sublimation systematically, as a means of recognition of the alkaloids, &c., was Helwig.[339] His method was to place a small quantity (from ½ to 1/4000 of a mgrm.) in a depression on platinum foil, cover it with a slip of glass, and then carefully heat by a small flame. After Helwig, Dr. Guy[340] greatly improved the process by using porcelain discs, and more especially by the adoption of a convenient apparatus, which may be termed “the subliming cell.” It is essentially composed of a ring of glass from ⅛ to ⅔ of an inch in thickness, such as may be obtained by sections of tubing, the cut surfaces being ground perfectly smooth. This circle is converted into a closed cell by resting it on one of the ordinary thin discs of glass used as a covering for microscopic purposes, and supporting a similar disc. The cell was placed on a brass plate, provided with a nipple, which carried a thermometer, and was heated by a small flame applied midway between the thermometer and the cell; the heat was raised very gradually, and the temperature at which any change took place was noted. In this way Dr. Guy made determinations of the subliming points of a large number of substances, and the microscopic appearances of the sublimates were described with the greatest fidelity and accuracy. On repeating with care Dr. Guy’s determinations, however, I could in no single instance agree with his subliming points, nor with the apparatus he figures and describes could two consecutive observations exactly coincide. Further, on examining the various subliming temperatures of substances, as stated by different authors, the widest discrepancies were found--differences of 2 or even 3 degrees might be referred to errors of observation, a want of exact coincidence in the thermometers employed, and the like; but to what, for example, can we ascribe the irreconcilable statements which have been made with regard to theine? According to Strauch, this substance sublimes at 177°; according to Mulder, at 184·7°. But that both of these observations deviate more than 70° from the truth may be proved by any one who cares to place a few mgrms. of theine, enclosed between two watch-glasses, over the water-bath; in a few minutes a distinct sublimate will condense on the upper glass, and, in point of fact, theine will be found to sublime several degrees below 100°.

[339] Das Mikroskop in der Toxicologie.

[340] Pharm. Journ. Trans. (2), viij. 719; ix. 10, 58. Forensic Medicine, London, 1875.

Since this great divergency of opinion is not found either in the specific gravity, or the boiling-points, or any of the like determinations of the physical properties of a substance, it is self-evident that the processes hitherto used for the determination of subliming points are faulty. The sources of error are chiefly--

(1.) Defects in the apparatus employed--the temperature read being rather that of the metallic surface in the immediate vicinity of the thermometer than of the substance itself.

(2.) The want of agreement among observers as to what should be called a sublimate--one considering a sublimate only that which is evident to the naked eye, another taking cognisance of the earliest microscopic film.

(3.) No two persons employing the same process.

With regard to the apparatus employed, I adopt Dr. Guy’s subliming cell; but the cell, instead of resting on a metallic solid, floats on a metallic fluid. For any temperature a little above 100° this fluid is mercury, but for higher temperatures fusible metal is preferable.

The exact procedure is as follows:--A porcelain crucible (a in fig.), about 3 inches in diameter, is nearly filled with mercury or fusible metal, as the case may be; a minute speck (or two or three crystals of the substance to be examined) is placed on a thin disc of microscopic covering glass, floated on the liquid, and the cell is completed by the glass ring and upper disc. The porcelain crucible is supported on a brass plate (b), fixed to a retort-stand in the usual way, and protected from the unequal cooling effects of currents of air by being covered by a flask (c), from which the bottom has been removed. The neck of the flask conveniently supports a thermometer, which passes through a cork, and the bulb of the thermometer is immersed in the bath of liquid metal. In the first examination of a substance the temperature is raised somewhat rapidly, taking off the upper disc with a forceps at every 10° and exchanging it for a fresh disc, until the substance is destroyed. The second examination is conducted much more slowly, and the discs exchanged at every 4° or 5°, whilst the final determination is effected by raising the temperature with great caution, and exchanging the discs at about the points of change (already partially determined) at every half degree. All the discs are examined microscopically. The most convenient definition of a sublimate is this--the most minute films, dots, or crystals, which can be observed by ¼-inch power, and which are obtained by keeping the subliming cell at a definite temperature for 60 seconds. The commencement of many sublimates assumes the shape of dots of extraordinary minuteness, quite invisible to the unaided eye; and, on the other hand, since the practical value of sublimation is mainly as an aid to other methods for the recognition of substances, if we go beyond short intervals of time, the operation, otherwise simple and speedy, becomes cumbersome, and loses its general applicability.

There is also considerable discrepancy of statement with regard to the melting-point of alkaloidal bodies; in many instances a viscous state intervenes before the final complete resolution into fluid, and one observer will consider the viscous state, the other complete fluidity, as the melting-point.

In the melting-points given below, the same apparatus was used, but the substance was simply placed on a thin disc of glass floating on the metallic bath before described (the cell not being completed), and examined from time to time microscopically, for by this means alone can the first drops formed by the most minute and closely-adherent crystals to the glass be discovered.

=Cocaine= melts at 93°, and gives a faint sublimate at 98°; if put between two watch-glasses on the water-bath, in fifteen minutes there is a good cloud on the upper glass.

=Aconitine= turns brown, and melts at 179° C.; it gives no characteristic sublimate up to 190°.

=Morphine=, at 150°, clouds the upper disc with nebulæ; the nebulæ are resolved by high magnifying powers into minute dots; these dots gradually become coarser, and are generally converted into crystals at 188°; the alkaloid browns at or about 200°.

=Thebaine= sublimes in theine-like crystals at 135°; at higher temperatures (160° to 200°), needles, cubes, and prisms are observed. The residue on the lower disc, if examined before carbonisation, is fawn-coloured with non-characteristic spots.

=Narcotine= gives no sublimate; it melts at 155° into a yellow liquid, which, on raising the temperature, ever becomes browner to final blackness. On examining the residue before carbonisation, it is a rich brown amorphous substance; but if narcotine be heated two or three degrees above its melting-point, and then cooled slowly, the residue is crystalline--long, fine needles radiating from centres being common.

=Narceine= gives no sublimate; it melts at 134° into a colourless liquid, which undergoes at higher temperatures the usual transition of brown colours. The substance, heated a few degrees above its melting-point, and then allowed to cool slowly, shows a straw-coloured residue, divided into lobes or drops containing feathery crystals.

=Papaverine= gives no sublimate; it melts at 130°. The residue, heated a little above its melting-point, and then slowly cooled, is amorphous, of a light-brown colour, and in no way characteristic.

=Hyoscyamine= gives no crystalline sublimate; it melts at 89°, and appears to volatilise in great part without decomposition. It melts into an almost colourless fluid, which, when solid, may exhibit a network not unlike vegetable parenchyma; on moistening the network with water, interlacing crystals immediately appear. If, however, hyoscyamine be kept at 94° to 95° for a few minutes, and then slowly cooled, the edges of the spots are arborescent, and the spots themselves crystalline.

=Atropine= (daturine) melts at 97°; at 123° a faint mist appears on the upper disc. Crystals cannot be obtained; the residue is not characteristic.

=Solanine.=--The upper disc is dimmed with nebulæ at 190°, which are coarser and more distinct at higher temperatures; at 200° it begins to brown, and then melts; the residue consists of amber-brown, non-characteristic drops.

=Strychnine= gives a minute sublimate of fine needles, often disposed in lines, at 169°; about 221° it melts, the residue (at that temperature) is resinous.

=Brucine= melts at 151° into a pale yellow liquid, at higher temperatures becoming deep-brown. If the lower disc, after melting, be examined, no crystals are observed, the residue being quite transparent, with branching lines like the twigs of a leafless tree; light mists, produced rather by decomposition than by true sublimation, condense on the upper disc at 185°, and above.

=Saponin= neither melts nor sublimes; it begins to brown about 145°, is almost black at 185°, and quite so at 190°.

=Delphinine= begins to brown about 102°; it becomes amber at 119°, and melts, and bubbles appear. There is no crystalline sublimate; residue not characteristic.

=Pilocarpine= gives a distinct crystalline sublimate at 153°; but thin mists, consisting of fine dots, may be observed as low as 140°. Pilocarpine melts at 159°; the sublimates at 160° to 170° are in light yellow drops. If these drops are treated with water, and the water evaporated, feathery crystals are obtained; the residue is resinous.

=Theine= wholly sublimes; the first sublimate is minute dots, at 79°; at half a degree above that very small crystals may be obtained; and at such a temperature as 120°, the crystals are often long and silky.

=Theobromine= likewise wholly sublimes; nebulæ at 134°, crystals at 170°, and above.

=Salicin= melts at 170°; it gives no crystalline sublimate. The melted mass remains up to 180° almost perfectly colourless; above that temperature browning is evident. The residue is not characteristic.

=Picrotoxin= gives no crystalline sublimate. The lowest temperature at which it sublimes is 128°; the usual nebulæ then make their appearance; between 165° and 170° there is slight browning; at 170° it melts. The residue, slowly cooled, is not characteristic.

=Cantharidin= sublimes very scantily between 82° and 83°; at 85° the sublimate is copious.

The active principles of plants may, in regard to their behaviour to heat, be classed for practical purposes into--

1. Those which give a decided crystalline sublimate: (a.) Below 100°, e.g., cocaine, theine, thebaine, cantharidin. (b.) Between 100° and 150°, e.g., quinetum. (c.) Between 150° and 200°, e.g., strychnine, morphine, pilocarpine. 2. Those which melt, but give no crystalline sublimate: (a.) Below 100°, e.g., hyoscyamine, atropine. (b.) Between 100° and 150°, e.g., papaverine. (c.) Between 150° and 200°, e.g., salicin. (d.) Above 200°, e.g., solanine. 3. Those which neither melt nor give a crystalline sublimate, e.g., saponin.

§ 315. =Melting-point.=--The method of sublimation just given also determines the melting-point; such a determination will, however, seldom compare with the melting-points of the various alkaloids as given in text-books, because the latter melting-points are not determined in the same way. The usual method of determining melting-points is to place a very small quantity in a glass tube closed at one end; the tube should be almost capillary. The tube is fastened to a thermometer by means of platinum wire, and then the bulb of the thermometer, with its attached tube, is immersed in strong sulphuric acid or paraffin, contained in a flask. The thermometer should be suspended midway in the liquid and heat carefully applied, so as to raise the temperature gradually and equably. It will be found that rapidly raising the heat gives a different melting-point to that which is obtained by slowly raising the heat. During the process careful watching is necessary: most substances change in hue before they actually melt. A constant melting-point, however often a substance is purified by recrystallisation, is a sign of purity.

§ 316. =Identification by Organic Analysis.=--In a few cases (and in a few only) the analyst may have sufficient material at hand to make an organic analysis, either as a means of identification or to confirm other tests. By the vacuum process described in “Foods,” in which carbon and nitrogen are determined by measuring the gases evolved by burning the organic substance in as complete a vacuum as can be obtained, very minute quantities of a substance can be dealt with, and the carbon and nitrogen determined with fair accuracy. It is found in practice that the carbon determinations appear more reliable than those of the nitrogen, and there are obvious reasons why this should be so.

Theoretically, with the improved gas-measuring appliances, it is possible to measure a c.c. of gas; but few chemists would care to create a formula on less than 10 c.c. of CO₂. Now, since 10 c.c. of CO₂ is equal to 6·33 mgrms. of carbon, and alkaloids average at least half their weight of carbon, it follows that 12 mgrms. of alkaloid represent about the smallest quantity with which a reliable single combustion can be made.

The following table gives a considerable number of the alkaloids and alkaloidal bodies, arranged according to their content in carbon:--

TABLE SHOWING THE CONTENT OF CARBON AND NITROGEN IN VARIOUS ALKALOIDAL BODIES.

Carbon. Nitrogen.

Asparagin, 36·36 21·21 Methylamine, 38·71 45·17 Betaine, 44·44 10·37 Theobromine, 46·67 31·11 Theine, 49·48 28·86 Indican, 49·60 2·22 Muscarine, 50·42 11·77 Lauro-cerasin, 52·47 1·53 Amanitine, 57·69 13·46 Narceine, 59·63 3·02 Colchicine, 60·53 4·15 Oxyacanthine, 60·57 4·42 Solanine, 60·66 1·68 Trimethylamine, 61·02 23·73 Jervine, 61·03 5·14 Sabadilline, 61·29 3·46 Aconitine, 61·21 2·16 Nepaline, 63·09 2·12 Colchicein, 63·44 4·38 Veratroidine, 63·8 3·1 Narcotine, 63·92 3·39 Veratrine, 64·42 2·91 Delphinine, 64·55 3·42 Physostigmine, 65·49 15·27 Rhœadine, 65·79 3·65 Cocaine, 66·44 4·84 Gelsemine, 67·00 7·10 Conhydrine, 67·12 9·79 Staphisagrine, 67·5 3·6 Chelidonine, 68·06 12·34 Atropine, Hyoscyamine, 70·58 4·84 Sanguinarine, 70·59 4·33 Papaverine, 70·79 4·13 Delphinoidine, 70·9 3·9 Morphine and Piperine, 71·58 4·91 Berberine, 71·64 4·18 Codeine, 72·24 4·68 Thebaine, 73·31 4·50 Cytisine, 73·85 12·92 Nicotine, 74·08 17·28 Quinine, 75·02 8·64 Coniine, 76·81 11·20 Strychnine, 77·24 8·92 Curarine, 81·51 5·28

§ 317. =Quantitative Estimation of the Alkaloids.=--For medico-legal purposes the alkaloid obtained is usually weighed directly, but for technical purposes other processes are used. One of the most convenient of these is titration with normal or decinormal sulphuric acid, a method applicable to a few alkaloids of marked basic powers--e.g., quinine is readily and with accuracy estimated in this way, the alkaloid being dissolved in a known volume of the acid, and then titrated back with soda. If a large number of observations are to be made, an acid may be prepared so that each c.c. equals 1 mgrm. of quinine. A reagent of general application is found in the so-called Mayer’s reagent, which consists of 13·546 grms. of mercuric chloride, and 49·8 grms. of iodide of potassium in a litre of water. Each c.c. of such solution precipitates--

Of Strychnine, ·0167 grm. „ Brucine, ·0233 „ „ Quinine, ·0108 „ „ Cinchonine, ·0102 „ „ Quinidine, ·0120 „ „ Atropine, ·0145 „ „ Aconitine, ·0268 „ „ Veratrine, ·0269 „ „ Morphine, ·0200 „ „ Narcotine, ·0213 „ „ Nicotine, ·00405 „ „ Coniine, ·00416 „

The final reaction is found by filtering, from time to time, a drop on to a glass plate, resting on a blackened surface, and adding the test until no precipitate appears. The results are only accurate when the strength of the solution of the alkaloid is about 1 : 200; so that it is absolutely necessary first to ascertain approximatively the amount present, and then to dilute or concentrate, as the case may be, until the proportion mentioned is obtained.

A convenient method of obtaining the sulphate of an alkaloid for quantitative purposes, and especially from organic fluids, is that recommended by Wagner. The fluid is acidulated with sulphuric acid, and the alkaloid precipitated by a solution of iodine in iodide of potassium. The precipitate is collected and dissolved in an aqueous solution of hyposulphite of soda. The filtered solution is again precipitated with the iodine reagent, and the precipitate dissolved in sulphurous acid, which, on evaporation, leaves behind the pure sulphate of the base.

It is also very useful for quantitative purposes to combine an alkaloid with gold or platinum, by treating the solution with the chlorides of either of those metals--the rule as to selection being to give that metal the preference which yields the most insoluble and the most crystallisable compound.

The following table gives the percentage of gold or platinum left on ignition of the double salt:--

Gold. Platinum.

Atropine, 31·57 ... Aconitine 20·0 ... Amanitine, 44·23 ... Berberine, 29·16 18·11 Brucine, ... 16·52 Cinchonine, ... 27·36 Cinchonidine, ... 27·87 Codeine, ... 19·11 Coniine, ... 29·38 Curarine, ... 32·65 Delphinine, 26·7 ... Delphinoidine, 29·0 15·8 Emetine, ... 29·7 Hyoscyamine, 34·6 ... Morphine, ... 19·52 Muscarine, 43·01 ... Narcotine, 15·7 15·9 Narceine, ... 14·52 Nicotine, ... 34·25 Papaverine, ... 17·82 Pilocarpine, 35·5 23·6 to 25·2. Piperine, ... 12·7 Quinine, 40·0 26·26 Strychnine, 29·15 18·16 Thebaine, ... 18·71 Theine, 37·02 24·58 Theobromine, ... 25·55 Veratrine, 21·01 ...

II.--Liquid Volatile Alkaloids.

THE ALKALOIDS OF HEMLOCK--NICOTINE--PITURIE--SPARTEINE.

1. THE ALKALOIDS OF HEMLOCK (CONIUM).

§ 318. The Conium maculatum, or spotted hemlock, is a rather common umbelliferous plant, growing in waste places, and flowering from about the beginning of June to August. The stem is from three to five feet high, smooth, branched, and spotted with purple; the leaflets of the partial involucres are unilateral, ovate, lanceolate, with an attenuate point shorter than the umbels; the seeds are destitute of vittæ, and have five prominent crenate wavy ridges. The whole plant is fœtid and poisonous. Conium owes its active properties to a volatile liquid alkaloid, Coniine, united with a crystalline alkaloid, Conhydrine.

§ 319. =Coniine= (=conia=, =conicine=), (C₈H₁₇N)--specific gravity 0·862 at 0°; melting-point, -2·5°; boiling-point, 166·6°. Pure coniine has been prepared synthetically by Ladenburg, and found to be propyl-piperidine C₅H₁₀NC₃H₇, but the synthetically-prepared piperidine has no action on polarised light. By uniting it with dextro-tartaric acid, and evaporating, it is possible to separate the substance into dextro-propyl-piperidine and lævo-propyl-piperidine. The former is in every respect identical with coniine from hemlock; it is a clear, oily fluid, possessing a peculiarly unpleasant, mousey odour. One part is soluble in 150 parts of water,[341] in 6 parts of ether, and in almost all proportions of amyl alcohol, chloroform, and benzene. It readily volatilises, and, provided air is excluded, may be distilled unchanged. It ignites easily, and burns with a smoky flame. It acts as a strong base, precipitating the oxides of metals and alkaline earths from their solutions, and it coagulates albumen. Coniine forms salts with hydrochloric acid (C₈H₁₅N.HCl), phosphoric acid, iodic acid, and oxalic acid, which are in well-marked crystals. The sulphate, nitrate, acetate, and tartrate are, on the other hand, non-crystalline.

[341] The saturated watery solution of coniine at 15°, becomes cloudy if gently warmed, and clears again on cooling.

If coniine is oxidised with nitric acid, or bichromate of potash, and diluted sulphuric acid, butyric acid is formed; and since the latter has an unmistakable odour, and other characteristic properties, it has been proposed as a test for coniine. This may be conveniently performed thus:--A crystal of potassic bichromate is put at the bottom of a test-tube, and some diluted sulphuric acid with a drop of the supposed coniine added. On heating, the butyric acid reveals itself by its odour, and can be distilled into baryta water, the butyrate of baryta being subsequently separated in the usual way, and decomposed by sulphuric acid, &c.

Another test for coniine is the following:--If dropped into a solution of alloxan, the latter is coloured after a few minutes an intense purple-red, and white needle-shaped crystals are separated, which dissolve in cold potash-lye into a beautiful purple-blue, and emit an odour of the base.[342] Dry hydrochloric acid gives a purple-red, then an indigo-blue colour, with coniine; but if the acid is not dry, there is formed a bluish-green crystalline mass. This test, however, is of little value to the toxicologist, the pure substance alone responding with any definite result.

[342] Schwarzenbach, Vierteljahrsschr. f. prakt. Pharm., viij. 170.

The ordinary precipitating agents, according to Dragendorff, act as follows:--

Potass bismuth iodide. 1 : 2000, a strong orange precipitate. 1 : 3000. The drop of the reagent is surrounded with a muddy border. 1 : 4000. The drop of the reagent is surrounded with a muddy border. 1 : 5000, still perceptible. 1 : 6000. The last limit of the reaction.

Phosphomolybdic acid gives a strong yellow precipitate; limit, 1 : 5000.

Potass. mercuric iodide gives a cheesy precipitate; limit, 1 : 1000 in neutral, 1 : 800 in acid, solutions.

Potass. cadmic iodide gives an amorphous precipitate, 1 : 300. The precipitate is soluble in excess of the precipitant. (Nicotine, under similar circumstances, gives a crystalline precipitate.)

Flückiger recommends the following reaction:[343]--“Add to 10 drops of ether in a shallow glass crystallising dish 2 drops of coniine, and cover with filter paper. Set upon the paper a common-sized watch-glass containing bromine water, and invert a beaker over the whole arrangement. Needle-shaped crystals of coniine hydro-bromine soon form in the dish as well as in the watch-glass.” Hydrochloric acid, used in the same way, instead of bromine water, forms with coniine microscopic needles of coniine hydrochlorate; both the hydro-bromide and the hydrochlorate doubly refract light. Nicotine does not respond to this reaction.

[343] Reactions, by F. A. Flückiger, Detroit, 1893.

Coniine forms with carbon disulphide a thiosulphate and a sulphite. If carbon disulphide, therefore, be shaken with an aqueous solution of coniine, the watery solution gives a brown precipitate with copper sulphate, colours ferric chloride solution dark brown red, and gives a milky opalescence with dilute acids. If coniine itself is added to carbon disulphide, there is evolution of heat, separation of sulphur, and formation of thiosulphate. Nicotine does not respond to this reaction.

§ 320. =Other Coniine Bases.=--Methyl- and ethyl-coniine have been prepared synthetically, and are both similar in action to coniine, but somewhat more like curarine. By the reduction of coniine with zinc dust conyrine (C₈H₁₁N) is formed; between coniine and conyrine stands coniceine (C₈H₁₅NO). De Coninck has made synthetically by the addition of 6 atoms of hydrogen to β collidine, a new fluid alkaloid (C₈H₁₁N + 6H = C₈H₁₇N), which he has called isocicutine: it has the same formula as coniine. Paraconiine Schiff prepared synthetically from ammonia and normal butyl aldehyde; it has the formula C₈H₁₅N, and therefore differs from coniine in containing two atoms less of hydrogen. All the above have a similar physiological action to coniine. α-stillbazoline (C₁₁H₁₉N), prepared by Baurath from benzaldehyde and picoline, is analogous to coniine, and according to Falck has similar action, but is more powerful.

§ 321. =Pharmaceutical Preparations.=--The percentage of coniine in the plant itself, and in pharmaceutical preparations, can be approximately determined by distilling the coniine over, in a partial vacuum,[344] and titrating the distillate with Mayer’s reagent, each c.c. = about ·00416 grm. of coniine. It appears to be necessary to add powdered potassic chloride and a small quantity of diluted sulphuric acid before titrating, or the precipitate does not separate. In any case, the end of the reaction is difficult to observe.[345]

[344] This is easily effected by uniting a flask containing the alkaloidal fluid, air-tight, with a Liebig’s condenser and a receiver, the latter being connected with Bunsen’s water-pump, or one of the numerous exhausting apparatuses now in use in every laboratory.

[345] Dragendorff, Die Chemische Werthbestimmung einiger starkwirkender Droguen, St. Petersb., 1874.

The fresh plant is said to contain from about ·04 to ·09 per cent., and the fruit about 0·7 per cent. of coniine.

The officinal preparations are--the leaves, the fruit, a tincture of the fruit, an extract of the leaves, the juice of the leaves (Succus conii), a compound hemlock pill (composed of extract of hemlock, ipecacuanha, and treacle), an inhalation of coniine (Vapor conii), and a poultice (Cataplasma conii) made with the leaves.

§ 322. =Statistics of Coniine Poisoning.=--F. A. Falck[346] has been able to collect 17 cases of death recorded in medical literature, up to the year 1880, from either coniine or hemlock. Two of these cases were criminal (murders), 1 suicidal, 2 cases in which coniine had been used medicinally (in one instance the extract had been applied to a cancerous breast; in the other, death was produced from the injection of an infusion of hemlock leaves). The remaining 12 were cases in which the root, leaves, or other portions of the plant had been ignorantly or accidentally eaten.

[346] Prakt. Toxicologie, p. 273.

§ 323. =Effects on Animals.=--It destroys all forms of animal life. The author made some years ago an investigation as to its action on the common blow-fly. Droplets of coniine were applied to various parts of blow-flies, which were then placed under glass shades. The symptoms began within a minute by signs of external irritation, there were rapid motions of the wings, and quick and aimless movements of the legs. Torpor set in speedily, the buzz soon ceased, and the insects lay on their sides, motionless, but for occasional twitching of the legs. The wings, as a rule, became completely paralysed before the legs, and death occurred at a rather variable time, from ten minutes to two hours. If placed in a current of air in the sun, a fly completely under the influence of coniine may recover. Coniine causes in frogs, similar to curarine, peripheral paralysis of the motor nerves, combined with a transitory stimulation, and afterwards a paralysis of the motor centres; in frogs the paralysis is not preceded by convulsions. Dragendorff experimented on the action of coniine when given to five cats, the quantities used being ·05 to ·5 grm. The symptoms came on almost immediately, but with the smaller dose given to a large cat, no effect was witnessed until twenty-five minutes afterwards; this was the longest interval. One of the earliest phenomena was dilatation of the pupil, followed by weakness of the limbs passing into paralysis, the hinder legs being affected prior to the fore. The respiration became troubled, and the frequency of the breathing diminished; the heart in each case acted irregularly, and the sensation generally was blunted; death was preceded by convulsions. In the cases in which the larger dose of ·4 to ·5 grm. was administered, death took place within the hour, one animal dying in eight minutes, a second in eighteen minutes, a third in twenty minutes, and a fourth in fifty-eight minutes. With the smaller dose of ·051 grm. given to a large cat, death did not take place until eight hours and forty-seven minutes after administration.

§ 324. =Effects on Man.=--In a case recorded by Bennet,[347] and quoted in most works on forensic medicine, the symptoms were those of general muscular weakness deepening into paralysis. The patient had eaten hemlock in mistake for parsley; in about twenty minutes he experienced weakness in the lower extremities, and staggered in walking like a drunken man; within two hours there was perfect paralysis of both upper and lower extremities, and he died in three and a quarter hours. In another case, related by Taylor, the symptoms were also mainly those of paralysis, and in other instances stupor, coma, and slight convulsions have been noted.

[347] Edin. Med. and Surg. Journ., July 1845, p. 169.

§ 325. =Physiological Action.=--It is generally agreed that coniine paralyses, first the ends of the motor nerves, afterwards their trunks, and lastly, the motor centre itself. At a later period the sensory nerves participate. In the earlier stage the respiration is quickened, the pupils contracted, and the blood-pressure increased; but on the development of paralysis the breathing becomes slowed, the capillaries relaxed, and the blood-pressure sinks. Death takes place from cessation of the respiration, and not primarily from the heart, the heart beating after the breathing has stopped. Coniine is eliminated by the urine, and is also in part separated by the lungs, while a portion is, perhaps, decomposed in the body.

§ 326. =Post-mortem Appearances.=--There is nothing characteristic in the appearances after death.

=Fatal Dose.=--The fatal dose of coniine is not accurately known; it is about 150 mgrms. (2·3 grains). In the case of Louise Berger, 10 to 15 drops appear to have caused death in a few minutes. The auto-experiments of Dworzak, Heinrich, and Dillaberger would indicate that one drop may cause unpleasant symptoms. Albers, in the treatment of a woman suffering from cancer of the breast, witnessed convulsions and loss of consciousness from a third dose of 4 mgrms. (·06 grain); and Eulenberg, its full narcotic effects on a child after subcutaneous injection of 1 mgrm. (·015 grain).

§ 327. =Separation of Coniine from Organic Matters or Tissues.=--The substances are digested with water, acidulated with H₂SO₄, at a temperature not exceeding 40°, and then filtered. If the filtrate should be excessive, it must be concentrated; alcohol is then added, the liquid refiltered, and from the filtrate the alcohol separated by distillation.

On cooling, the acid fluid is agitated with benzene, and the latter separated in the usual way. The fluid is now alkalised with ammonia, and shaken up once or twice with its own volume of petroleum ether; the latter is separated and washed with distilled water, and the alkaloid is obtained almost pure. If the petroleum ether leaves no residue, it is certain that the alkaloid was not present in the contents of the stomach or intestine.

The affinity of coniine with ether or chloroform is such, that its solution in either of these fluids, passed through a dry filter, scarcely retains a drop of water. In this way it may be conveniently purified, the impurities dissolved by water remaining behind.

In searching for coniine, the stomach, intestines, blood, urine, liver, and lungs are the parts which should be examined. According to Dragendorff, it has been discovered in the body of a cat six weeks after death.

Great care must be exercised in identifying any volatile alkaloid as coniine, for the sources of error seem to be numerous. In one case[348] a volatile coniine-like ptomaine, was separated from a corpse, and thought to be coniine; but Otto found that in its behaviour to platinic chloride, it differed from coniine; it was very poisonous--·07 was fatal to a frog, ·44 to a pigeon, in a few minutes. In the seeds of Lupinus luteus there is a series of coniine-like substances,[349] but they do not give the characteristic crystals with hydrochloric acid.

[348] Otto, Anleitung z. Ausmittlung d. Gifte, 1875.

[349] Sievert, Zeitschrift für Naturwissenschaften.

2. TOBACCO--NICOTINE.

§ 328. The different forms of tobacco are furnished by three species of the tobacco plant, viz., Nicotianum tabacum, N. rustica, and N. persica.

Havanna, French, Dutch, and the American tobaccos are in the main derived from N. tabacum; Turkish, Syrian, and the Latakia tobaccos are the produce of N. rustica. There seems at present to be little of N. persica in commerce.

All the species of tobacco contain a liquid, volatile, poisonous alkaloid (Nicotine), probably united in the plant with citric and malic acids. There is also present in tobacco an unimportant camphor (nicotianin). The general composition of the plant may be gathered from the following table:--

TABLE SHOWING THE COMPOSITION OF FRESH LEAVES OF TOBACCO (POSSELT AND RIENMANN).

Nicotine, 0·060 Concrete volatile oil, 0·010 Bitter extractive, 2·870 Gum with malate of lime, 1·740 Chlorophyl, 0·267 Albumen and gluten, 1·308 Malic acid, 0·510 Lignine and a trace of starch, 4·969 Salts (sulphate, nitrate, and malate of potash, } chloride of potassium, phosphate and malate } 0·734 of lime, and malate of ammonia,) } Silica, 0·088 Water, 88·280 ------- 100·836

§ 329. =Quantitative Estimation of Nicotine in Tobacco.=--The best process (although not a perfectly accurate one) is the following:--25 grms. of the tobacco are mixed with milk of lime, and allowed to stand until there is no odour of ammonia; the mixture is then exhausted by petroleum ether, the ether shaken up with a slight excess of normal sulphuric acid, and titrated back by baryta water; the sulphate of baryta may be collected and weighed, so as to control the results. With regard to the percentage of nicotine in commercial tobacco, Kosutany found from 1·686 to 3·738 per cent. in dry tobacco; Letheby, in six samples, from 1·5 to 3·2 per cent.; whilst Schlössing gives for Havanna 2 per cent., Maryland 2·29 per cent., Kentucky 6·09 per cent., Virginian 6·87 per cent., and for French tobacco, quantities varying from 3·22 to 7·96 per cent. Again, Lenoble found in Paraguay tobacco from 1·8 to 6 per cent.; and Wittstein, in six sorts of tobacco in Germany, 1·54 to 2·72 per cent.

Mr. Cox[350] has recently determined the amount of nicotine in a number of tobaccos. The results are tabulated in the following table as follows:--

[350] Pharm. Journ., Jan. 20, 1894.

TABLE OF RESULTS, ARRANGED ACCORDING TO PER CENT. OF NICOTINE.

Variety examined. Nicotine per cent.

1. Syrian leaves (a), ·612 2. American chewing, ·935 3. Syrian leaves (b), 1·093 4. Chinese leaves, 1·902 5. Turkish (coarse cut), 2·500 6. Golden Virginia (whole strips), 2·501 7. Gold Flake (Virginia), 2·501 8. “Navy-cut” (light coloured), 2·530 9. Light returns (Kentucky), 2·733 10. “Navy-cut” (dark “all tobacco”), 3·640 11. Best “Birds-eye,” 3·931 12. Cut Cavendish (a), 4·212 13. “Best Shag” (a), 4·907 14. “Cut Cavendish” (b), 4·970 15. “Best Shag” (b), 5·000 16. French tobacco, 8·711 17. Algerian tobacco (a), 8·813 18. Algerian tobacco (b), 8·900

It is therefore obvious that the strength of tobacco in nicotine varies between wide limits.

Twenty-five grammes (or more or less, according to the amount of the sample at disposal) of the dried and powdered tobacco were intimately mixed with slaked lime, and distilled in a current of steam until the condensed steam was no longer alkaline; the distillate was slightly acidulated with dilute H₂SO₄, and evaporated to a conveniently small bulk. This was made alkaline with soda, and agitated repeatedly with successive portions of ether. The separated batches of ethereal solution of nicotine were then mixed and exposed to the air in a cool place. This exposure to the air carries away ammonia, if any be present, as well as ether.

Water was added to the ethereal residue, and the amount of nicotine present determined by decinormal H₂SO₄, using methyl-orange as an indicator. One c.c. of decinormal H₂SO₄ represents 0·0162 gramme of nicotine (C₁₀H₁₄N₂).

§ 330. =Nicotine= (C₁₀H₁₄N₂).--Hexahydro dipyridyl (C₅H₄N)₂H₆, when pure, is an oily, colourless fluid, of 1·0111, specific gravity at 15°.[351] It evaporates under 100° in white clouds, and boils at about 240°, at which temperature it partly distils over unchanged, and is partly decomposed--a brown resinous product remaining. It volatilises with aqueous and amyl alcohol vapour notably, and is not even fixed at -10°. It has a strong alkaline reaction, and rotates a ray of polarised light to the right. Its odour, especially on warming, is strong and unpleasantly like tobacco, and it has a sharp caustic taste. It absorbs water exposed to the air, and dissolves in water in all proportions, partly separating from such solution on the addition of a caustic alkali. The aqueous solution acts in many respects like ammonia, saturating acids fully, and may therefore be in certain cases estimated with accuracy by titration, 49 parts of H₂SO₄ corresponding to 162 of nicotine. It gives on oxidation nicotinic acid = m(β) pyridincarbo acid C₅H₄N(COOH), and by oxidation with elimination of water dipyridyl (C₅H₄N)₂, and through reduction dipiperydil (C₅H₁₀N)₂.

[351] J. Skalweit, Ber. der. deutsch. Chem. Gesell., 14, 1809.

Alcohol and ether dissolve nicotine in every proportion; if such solutions are distilled, nicotine goes over first. The salts which it forms with hydrochloric, nitric, and phosphoric acids crystallise with difficulty; tartaric and oxalic acid form white crystalline salts, and the latter, oxalate of nicotine, is soluble in alcohol, a property which distinguishes it from the oxalate of ammonia. The best salts are the oxalate and the acid tartrate of nicotine, from which to regenerate nicotine in a pure state.

Hydrochloride of nicotine is more easily volatilised than the pure base. Nicotine is precipitated by alkalies, &c., also by many oxyhydrates, lead, copper, &c. By the action of light, it is soon coloured yellow and brown, and becomes thick, in which state it leaves, on evaporation, a brown resinous substance, only partly soluble in petroleum ether.

A very excellent test for nicotine, as confirmatory of others, is the beautiful, long, needle-like crystals obtained by adding to an ethereal solution of nicotine a solution of iodine in ether. The crystals require a few hours to form.

Chlorine gas colours nicotine blood-red or brown; the product is soluble in alcohol, and separates on evaporation in crystals.

Cyanogen also colours nicotine brown; the product out of alcohol is not crystalline. Platin chloride throws down a reddish crystalline precipitate, soluble on warming; and gallic acid gives a flocculent precipitate. A drop of nicotine poured on dry chromic acid blazes up, and gives out an odour of tobacco camphor; if the ignition does not occur in the cold, it is produced by a gentle heat. It is scarcely possible to confound nicotine with ammonia, by reason of its odour; and, moreover, ammonia may always be excluded by converting the base into the oxalate, and dissolving in absolute alcohol.

On the other hand, a confusion between coniine and nicotine is apt to occur when small quantities only are dealt with. It may, however, be guarded against by the following tests:--

(1.) If coniine be converted into oxalate, the oxalate dissolved in alcohol, and coniine regenerated by distillation (best in vacuo) with caustic lye, and then hydrochloric acid added, a crystalline hydrochlorate of coniine is formed, which doubly refracts light, and is in needle-shaped or columnar crystals, or dendritic, moss-like forms. The columns afterwards become torn, and little rows of cubical, octahedral, and tetrahedral crystals (often cross or dagger-shaped) grow out of yellow amorphous masses. Crystalline forms of this kind are rare, save in the case of dilute solutions of chloride of ammonium (the presence of the latter is, of course, rendered by the treatment impossible); and nicotine does not give anything similar to this reaction.

(2.) Coniine coagulates albumen; nicotine does not.

(3.) Nicotine yields a characteristic crystalline precipitate with an aqueous solution of mercuric chloride; the similar precipitate of coniine is amorphous.

(4.) Nicotine does not react with CS₂ to form thiosulphate (see p. 266).

§ 331. =Effects on Animals.=--Nicotine is rapidly fatal to all animal life--from the lowest to the highest forms. That tobacco-smoke is inimical to insect-life is known to everybody; very minute quantities in water kill infusoria. Fish of 30 grms. weight die in a few minutes from a milligram of nicotine; the symptoms observed are rapid movements, then shivering and speedy paralysis, with decreased motion of the gills, and death. With frogs, if doses not too large are employed, there is first great restlessness, then strong tetanic convulsions, and a very peculiar position of the limbs; the respiration after fatal doses soon ceases, but the heart beats even after death. Birds also show tetanic convulsions followed by paralysis and speedy death. The symptoms witnessed in mammals poisoned by nicotine are not essentially dissimilar. With large doses the effect is similar to that of prussic acid--viz., a cry, one or two shuddering convulsions, and death. If the dose is not too large, there is trembling of the limbs, excretion of fæces and urine, a peculiar condition of stupor, a staggering gait, and then the animal falls on its side. The respiration, at first quickened, is afterwards slowed, and becomes deeper than natural; the pulse, also, with moderate doses, is first slowed, then rises in frequency, and finally, again falls. Tetanic convulsions soon develop, during the tetanus the pupils have been noticed to be contracted, but afterwards dilated, the tongue and mouth are livid, and the vessels of the ear dilated. Very characteristic of nicotine poisoning as witnessed in the cat, the rabbit, and the dog, is its peculiarly violent action, for after the administration of from one to two drops, the whole course from the commencement of symptoms to the death may take place in five minutes. F. Vas has drawn the smoke of tobacco from an immense pipe, and condensed the products; he finds the well-washed tarry products without physiological action, but the soluble liquid affected the health of rabbits,--they lost weight, the number of the blood corpuscles was decreased, and the hæmoglobin of the blood diminished.[352]

[352] Archiv. f. Exper. Pathol. u. Pharm., Bd. 33.

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