Notes on materia medica and therapeutics

Preface

In preparing the fourth edition of these notes, the editor has been thoroughly mindful of the introduction of several valuable drugs since the publication of the last edition, and the prominence given in recent lectures by Prof. Thomson to some of these, and the desirability of having fuller notes on some of the older remedies, have rendered necessary the issue of the present edition. Advantage has been taken of the occasion to make what is practically a new work, for the present notes are based upon stenographic .reports of the lectures delivered during the winter session of 1888-89, the material in the older editions for obvious reasons having been drawn upon to a slight extent only.

To render the work as complete as possible, several monographs by Prof. Thomson, bearing directly upon the uses and administration of drugs, have been introduced. Other new features are the frequent use of cross-references and a summary at the end of each of the principal drugs.

Owing to the nature of the work, the appearance of a few errors, typographical and otherwise, is almost unavoidable, but none of them, I trust, will be found misleading.

IV PREFACE.

To Mr. Edward Merrins I am indebted for the full and careful notes of Prof. Thomson's lectures, and for invaluable aid in the preparation of the material for the press.

If these notes are found helpful by the student, the object of their publication will have been attained.

W. M. H. McEnroe, M.D. 55 East 11th Street, October, 1889.

Table Of Contents

PAGE

PART I.— DISINFECTANT REMEDIES. Introductory to Disinfectants, 11

General Disinfectants, 19

Special Disinfectants,

Lime, ' 20

Charcoal, 22

Carbolic Acid and allied Compounds, 24

Chlorine, . . 31

Bromine, 32

Sulphur, 34

Iodine, 34

Boracic Acid, 35

Permanganate of Potash, 35

Uses of Disinfectants in the treatment of Special Diseases, ... 36

PART IL— MEDICINAL REMEDIES.

Introductory to Medicinal Remedies, 45

CLASS I.— ORGANIC OR DISEASE MEDICINES. 1. Restoratives:

Iron, 62

Phosphorus, 73

Quinine 76

Vegetable Bitters, 87

Mineral Acids, 90

Alkalies, 95

Mineral Waters, 97

VI

TABLE OF CONTEXTS.

PAGE

2. Alteratives :

Iodine and Compounds, Ill

Bromides, 117

Silver, 133

Zinc, 135

Copper, 136

Bismuth, 136

Colcliicum, 136

CLASS II.— FUNCTIONAL OR SYMPTOM MEDICINES.

Neurotics ;

Introductory,

. 141

Narcotics,

Opium,

Alcohol,

. 168

Ethers,

Belladonna,

. 179

Hyoscyamus, .

Stramonium,

Cannabis Indica,

Stimulant Neurotics,

Strophanthus, ....

Nitroglycerin, ......

Caffeine,

Ammonia, ....

Stiychnine, ....

Camphor, ....

Asafcetida, ....

. . . . .204

Valeriana, -

Depressant Neurotics,

Veratrum Yiride, ....

Tartar Emetic,

Hydrocyanic Acid, ....

Conium,

Gelsemium,

... . 215

TABLE OF CONTENTS. Vll

PAGE

Anaesthetics, 219

Cocaine, 219

Chloral 220

Paraldehyd, 222

Sulfonal, . 223

Phenacetin, 223

2. Eliminatives or Glandular Medicines:

a. Cathartics,

Calomel, ' . 232

Castor Oil, 233

Aloes, 235

Rhubarb, 235

Cascara Sagrada, ......... 237

Colocynth, 238

Scammony, 239

Jalap, 239

Podophyllum, 239

Elaterium, 240

Camboge, ". 240

Senna, 241

Compound Cathartic Pills, 241

Croton Oil, 241

Sulphate of Magnesium (Epsom Salts), 243

Sulphate of Sodium (Glauber's Salts), 243

Cream Tartar, 243

Tartrate of Potassium and Sodium, 244

Phosphate of Sodium, 244

b. Emetics,

Apomorphine, 245

Ipecacuanha, 246

Sulphate of Zinc, 248 c. Diuretics,

Squill, 251

Turpentine, 251

Buchu, 252

Cream Tartar, 253

Vlll TABLE OF CONTENTS.

PAGE

d. J)iap7ioretics,

Dover's Powder, 256

Sweet Spirit of Nitre, . 256

Jaborandi, 257

e. Expectorants, 258

3. Astringents .

Plumbi acetatis, 265

Liquor Ferri Subsulphatis, 268

Liquor Ferri Pernitratis, . . ... . . . 268

Alum, 269

Tannin— Tannic Acid, . 269

PART III.— NON-MEDICINAL MEDICINES. Cold, 278

Dry Heat, , 285

CLASSIFICATION OF MEDICINES.

All Kemedies may be divided into three classes: Medicinal, Non-Medicinal, and Disinfectant.

A Medicine is a remedy which cannot act until it enters the Circulation in a state of solution.

The circulation includes not only the blood, but also the interstitial fluid outside the capillaries, and which is the real nutritive fluid of the tissues. That it is in nearly as rapid movement as the blood itself, is shown by the quick diffusion of hypodermatic injections.

Non-medicinal Kemedies are those which act without entering the Circulation, as Counter-irritants, Blisters, Caustics, Electricity, Heat, Cold, Baths, Change of Scene or of Air, Massage, etc.

Disinfectants either destroy the agents which cause the decomposition of organic textures and fluids, or else neutralize the poisons generated by the growth or activity of those agents.

MEDICINES.

Medicines are divided into two classes: 1. Organic or Disease Medicines. 2. Functional or Symptom Medicines.

The Organic Medicines are those which act upon and modify the tissues or fluids of the body, so that after their action the system is not in the same state that it was in before their administration. Examples : Cod-Liver Oil in nutritive disorders, Iron in Anaemia, Mercury in Syphilis, etc.

The Functional Medicines produce no recognizable effect upon the various bodily organs, but affect their functions instead.

The function of an organ is its work, as Respiration the function of the Lungs ; Circulation the function of the Heart and Blood Vessels ; Secretion

NOTES ON MATERIA MEDICA.

the function of the Glands, etc. Thus Ammonia may stimulate the heart's work and Aconite depress it, so as to accelerate or slow the circulation accordingly, but neither of these agents affects the structure of the heart itself. Opium or Tobacco leaves no traces on the Nerve Tissues, though taken for years for their effects on Nerve Functions.

The two Classes of Medicines present the following contrasts in their characters :

ORGANIC OR DISEASE MEDICINES.

They are given for Diseases or Morbid Conditions, not for Symptoms.

Thus Potassium Iodide is given not to relieve the pain of a syphilitic node, but to remove the node itself.

They relieve symptoms, therefore, only indirectly, by removing their cause.

They show the properties which lead to their use as medicines only in disease.

Iron or Cod-Liver Oil does not strengthen persons in health. Mercury is a great restorer, provided there be Syphilis, etc.

By a Morbid Condition, in distinction from a Disease, is meant a state like Ansemia or like Dropsy, which, though definite, yet is the result of quite different causes in different

FUNCTIONAL OR SYMPTOM MEDI- CINES.

They are given for Symptoms, not for Diseases.

_ Thus Opium is given in inflammation, fractures, cancer, neuralgia, etc., only for what these have in common — the symptom pain.

Symptom Medicines act in health as well as in disease.

Emetics or Cathartics, or Neurotics, will act the same whether taken by the well or by the sick. Hence their actions are often studied by experiments on animals.

Their action is never secured by one dose, but only by repeated doses. They, therefore, require time for their operation, because they are cumulative, and hence their effect is more permanent.

Their whole action is secured by one dose, and no different effect follows upon repeated doses. Hence they are not cumulative, and their effect is transient.

Thus half a dose of a Cathartic or of an Emetic fails to produce any characteristic effect. Repeated doses of a Neurotic, also, only repeat the symptoms of the first dose without adding any further effect on the disease or on the symptom. Thus Stramonium may relieve the symptom of spasm in asthma for a lifetime, but the last dose has no more helped to cure the asthma than the first one.

CLASSIFICATION OF MEDICINES.

They should not produce symptoms. The patient should not know that he is taking anything except by noticing an improvement in his disease.

Whenever they produce symptoms of their own, they are either given in excess or else they are not suited to the case.

Thus iron disagrees when it produces headache. Quinine should not be pushed beyond the symptoms of cinch onism. Mercury ceases to be remedial after salivation begins, and iodine after the symptoms of iodism develop, etc.

Disease Medicines are most commonly employed in the treatment of Chronic Diseases.

Thus Cod-Liver Oil, while valuable in Chronic Pulmonary Diseases, is useless in Acute Pneumonia. Iron is not given for the debility of fever, etc.

Chronic Diseases are due to faults of the constitution, either inherited or acquired, and hence only organic medicines can permanently benefit them. The term Chronic shows that they have no tendency to spontaneous recovery.

In some cases a Disease Medicine can be made to act as a Symptom ^»Iedieine, by giving it in the symptom way, viz., in one large dose.

Thus Mercury in a large dose of calomel becomes a cathartic, but if so it ceases at once to act against any syphilis present in the system, for it cannot be both a Disease Medicine and a Symptom Medicine at the same time.

They do not act unless they do produce symptoms. The dose of all Symptom Medicines is the quantity which will produce the symptoms characteristic of the medicine, and nothing less.

Thus, while the ordinary dose oi opium for an adult is one grain, it may require in peritonitis twenty grains before a symptom of opium is obtained; if so, the dose then is twenty grains.

Symptom Medicines are most commonly employed in the management of Acute Diseases.

Acute Diseases, as inflammations, fevers, etc., are of the nature of accidents and may occur in the young and healthy. If uncomplicated, Acute Diseases are self -limited and terminate, with rare exceptions, within six weeks. Symptom Medicines are called for in them to relieve suffering and to prevent complications, but not to cure the disease, which rather must be watched while it runs its course.

CLASS I.— ORGANIC OR DISEASE MEDICINES.

Division I. — Restoratives.

Characters: I. They are medicines which, are natural to the system, either because they are themselves ingredients thereof, or else analogous to what is so.

II. They act by making up a deficiency in the system, by being themselves the thing deficient, or else similar to it. They are, therefore, of the nature of foods, and hence are beneficial only when the system is starved of the ingredient to which they correspond. Examples: Iron in anaemia, Cod-Liver Oil when blood fat is wanting, etc.

Restoratives and Disinfectants are the only prophylactics.

Division II. — Alteratives.

Characters: I. They are Organic or Disease Medicines unnatural to the system.

They are, therefore, more or less poisonous, and this fact is to be remembered, because, though all Symptom Medicines are also unnatural to the system, yet complete recovery from the most active of them, like Opium or Aconite, is a question of hours only, while recovery from the injury of organic poisons may be very slow.

II. They act in an unknown way only against certain special diseases or morbid conditions. The range of their remedial applications is therefore more limited than with restoratives.

CLASSIFICATION OF MEDICINES.

Potassium Iodide acts promptly against syphilitic periostitis, but not to the same degree in other forms of periostitis. Colchicum is the remedy for gouty arthritis, but not for rheumatic arthritis, etc.

III. When they act as poisons they produce characteristic symptoms, such as salivation by mercury, or iodism, bromism, etc. When they do so, they cease to act as remedies, and the dose should be lessened to that which does not cause symptoms, or else they must be abandoned. As their poisonous effects are both different from their remedial effects and inconsistent with them, an important rule in their lengthened administration is to conjoin restoratives with them to postpone their poisonous effects as long as possible.

CLASS II.— FUNCTIONAL OR SYMPTOM MEDICINES. Division I. — Neurotics.

Characters: I. They are medicines which produce their symptoms by affecting some nerve functions. Neurotics never act upon the whole nervous system, and hence the use of such terms as "general nervous stimulants or sedatives " is incorrect. The most widely operative neurotics, such as opium, are yet quite selective, and affect the functions of only a few out of the many nerve centres.

II. As they are purely functional remedies, neu" rotics cannot cure real nervous diseases like epilepsy, asthma, etc., as these diseases are generally the most constitutional of all diseases.

b NOTES ON MATERIA MEDICA.

The effect of neurotics is usually weakened by repetition, so that the doses have to be increased. Yet they promote the action of organic medicines when they relieve special symptoms of the disease. Thus opium and conium materially increase the efficacy of potassium iodide in syphilitic periostitis when there is much pain, and on the same principle chloral, by lessening reflex excitability, assists the bromides in epilepsy.

Neurotics may be divided into:

a. Those which are both Stimulants and Sedatives (commonly called Narcotics). These agents generally stimulate some nerve functions, while they simultaneously depress others. Thus opium stimulates some of the higher cerebral functions and also stimulates the heart, and at the same time blunts sensation and paralyzes the alimentary canal.

Or else these agents first stimulate certain functions and afterwards depress the same, but secondarily from exhaustion.

ft. Those which are Stimulants only of certain nerve functions. Examples: Ammonia on the heart, Valerian and Asafcetida on the abdominal ganglia, etc.

c. Those which are Sedatives only of certain nerve functions, as Hydrocyanic Acid of the respiratory function. ,

Division II. — Eliminatives or Glandular Medicines.

Characters: I. These medicines increase gland secretion. They are given more against complications occurring in the course of acute or of chronic diseases than against mere symptoms.

Thus fever arrests secretion, and therefore, if long continued, endangers life by the complication of starvation from deficiency of digestive secretions in the alimentary canal, and by the complication of self -poisoning from retained excretions. Eliminatives here are useful, not to eliminate the disease, but to modify these complications.

II. By them also the different gland secretions are sometimes made to act vicariously for some one deficient gland function, as when Cathartics and Diaphoretics are used in kidney disease.

These medicines are divided into:

a. Cathartics, which increase the secretion of the intestines.

h. Emetics, which act upon the secretions of the pharynx, stomach, liver, and duodenum in the act of emesis.

c. Diuretics, which act on the kidneys.

d. Diaphoretics, which act on the skm.

e. Expectorants, which act on the bronchial secretion.

Division III. — Astringents.

Characters: These medicines constringe muscular and fibrous tissues and diminish secretion. They are also employed for arresting haemorrhage by coagulating the blood.

They are divisible into:

a. Mineral Astringents.

I. Vegetable Astringents.

Part I. Disinfectant Remedies

DISINFECTANT REMEDIES.

GENERAL INTRODUCTORY.

Disinfectants are remedies which are used for the prevention of those diseases which come to us from without, and are not directly due to anything which is in the system itself. These diseases are accidents, and have nothing of the nature of constitutional diseases.

The causes of these diseases are external, and the patient is not directly responsible for an attack unless he wilfully places himself in those surroundings where he knows the disease exists. Thus, two persons may he attacked by small-pox, one haying unwittingly come in contact with a person suffering from the disease; to this man the disease is an accident. The other person wilfully, and with full knowledge of the fact, incurred the risk of infection ; this cannot be called an accident. Nevertheless, to both persons the cause of the disease came from without their own bodies. It was an external cause.

It is now almost the unanimous opinion of the medical profession that these extraneous, accidental diseases — of which smallpox may be taken as a type — are caused by living organisms, not by any physical or chemical agency. Disinfection means simply the endeavor to destroy these organisms, either directly by the disinfectant employed, or indirectly by the production of an agent inimical to their vitality; and hence any disease against which disinfectants can be successfully employed must be produced by these organisms. To speak, therefore, of eliminating the " poison " in these diseases shows an erroneous conception of the nature of their cause, for, irrespective of the dentification of the organisms by the microscope, the various processes occurring in the course of these accidental or "communicable " diseases differ in all their essential features from those produced by poisons. The word "poison " in its strict sense means a definite chemical substance, devoid of life, that produces disease or death after having entered the circulation; but the meaning of the term has been extended to embrace also those substances — e.g., caustics — which cause death or serious bodily harm by their chemical action upon the tissues with which they come in contact. That these diseases are due to living organisms and not to poisons is conclusively shown by the following facts: (1) In poisons, quantity is an essential element: a certain amount will prove fatal, a lesser amount will not be fatal, and a minute amount may act medicinally.

On the other hand, in these diseases quantity is unimportant, the small amount of virus introduced into a person's system by inoculation infecting him to as great an extent as though a much larger quantity had been used. (2) In the case of poisons, time is an unimportant element, for, though there may be delay in absorption, as soon as a poison enters the circulation its characteristic effects are immediately produced; but where diseases are dependent upon living organisms, there must be a certain period before the symptoms of disease are manifested. This latent period, called "incubation " (an unfortunate term, as it implies animal origin, and should be replaced by that of "germination"), is followed by the period of development, which is characterized by certain changes which are never reversed. (3) Following this period of development we have the most positive proof of the character of these morbid agents in the great feature of reproduction, as there is nothing in chemistry or physics that can reproduce itself. Thus, for example, the organisms in the minute quantity of variola -lymph introduced into the system by inoculation reproduce themselves to such an extent as to enable us to obtain from the person so infected a quantity sufficient to infect multitudes. This element of reproduction is the cause, and the only cause, of these diseases being dangerous. Immunity from the effects of any one of them depends on the virus being unable to reproduce itself in the system of the person exposed to its influence, and, conversely, the severity of the disease will be in proportion to the receptivity of the soil on which these organisms — or, as they might be termed, seeds — will fall. Thus, of five persons exposed to the influence of one of these communicable diseases, two may be violently affected by it and die, two may be totally unaffected by it, and one may be affected slightly. "With poisons, however, the results are invariable; a dose of strychnine, for instance, producing precisely the same effects in one person as in another. (4) The variations in type and severity of these diseases from year to year also show that they are dependent upon living organisms; for these variations never happen with poisons, but growths are constantly having fluctuations in their reproduction. (5) The transportation of poisons from one country to another does not affect their peculiar properties, but growths are very much affected by soil, climate, altitude, etc., and so we find that many of these diseases are endemic; for instance, cholera cannot ascend a mountain, and yellow fever is checked by frost.

It is thus shown that we have to deal with agents that live and grow, and which never originate spontaneously; and the microscope, which confirms these deductions, reveals to us the fact that we are living in an immense ocean of minute forms of organic life, compared with which the world of life we see around us with the naked eye is quite small. Eeasoning from analogy, and from the fact that no form of li'fe can live for itself, we should expect that this kingdom of microscopic life, by far the largest and most universal, must have very important relations to other departments of life, and this we find to be the case. Without the aid of these minute organisms there would be no vegetable growth, as the fermentation they produce is essential to the fertility of the soil; for it has been found that soil which has been sterilized will not support vegetable life. To a very large extent they furnish the microscopic nuclei to the atmosphere which serve for the precipitation of watery particles, and thus they assist in the formation of clouds; for in air which has been filtered through cotton, and thus rid of all solid matter, the introduction of steam is not followed by a ' ' cloud " or "mist," but it immediately condenses as water. If, therefore, we were living in a perfectly pure atmosphere, there would be

14 NOTES ON MATEEIA MEDICA.

no clouds and consequently no ram; the whole earth would be a desert, for as fast as water was evaporated from the ocean it would return, unable to find a resting place for its particles. What is still more important, however, is the fact that if it were not for these organisms nature would very soon be choked with her own dead. Decomposition of either animal or vegetable substances never occurs spontaneously, but is brought about by the agency of these organisms in a complex series of processes. In the putrefaction of ordinary butcher's meat, no less than eight kinds of organic life, differing in form, activity, and chemical results, succeed each other, in an order which is rarely reversed, before decomposition is complete, the processes being analogous to those in the decomposition of vegetable matter — e.g., alcoholic fermentation, where the alcoholic plant is succeeded by the acetic acid plant. These facts have an important and significant bearing on the subject of the growth of the organisms by which communicable diseases are produced, and they direct attention to a stage (the post-latent) of these diseases to which heretofore there has not been attached sufficient importance, but to which these facts give a very decided clue as to its actual existence.

Communicable diseases are characterized by a " latent stage," or, as it might now more correctly be termed, a "pre-latent stage " — the period of incubation or germination. This is followed by the period of development, after which comes the period of reproduction, to be succeeded by the apparent recovery of the patient. But the disease has not yet been conquered; the recovery is only apparent, for there now succeeds another latent stage, which may be termed the " post-latent." For instance, at the end of a certain time the kidneys may be affected after an attack of scarlet fever, and paralytic troubles may follow diphtheria; measles may end in chronic asthma, and measles and scarlet fever may both be succeeded by nasal catarrh and otorrhea. These manifestations of the post-latent stage are not the sequelae of the original complaint, but are indications of a new disease due to the development of other bacterial growths, because every one of these diseases due to an organism of its own prepares the way for another disease which but for it would not appear. We are thus living in a world of life which is ever ready to seize upon and destroy anything that shows a weakened vitality — a vitality insufficient to repel or overcome them.

This subject should be thoroughly studied, not so much to discover this or that disease, as to enable us to grasp the general laws of this microscopic world, and to infer from them facts which would be obscure if we studied the specific forms "by themselves. For instance, in phthisis, a bacterial disease — the microscope here affording us a means of diagnosis superior to that of physical exploration, as we can by its use determine with certainty the presence of the disease where otherwise we would be in doubt — there is the suggestive fact that it does not prevail anywhere in the world where the soil is permeable to water to the depth of about thirty feet; but in proportion as we come to soil which holds water two or three feet below the surface of the earth, there phthisis most extensively prevails. This disease, therefore, is due to the introduction into the system of germs which are dependent upon a certain condition of the soil, not to atmospheric bacteria; hence to get rid of the disease the soil must be dealt with.

In regard to the probable action of these germs ' in producing disease, there is no doubt but that the blood, in a large proportion of cases, is the medium of infection; for instance, in anthrax the bacilli seem to originate and multiply in the red blood-corpuscles, rendering them unfit to carry on their functions and thus causing death. More commonly, however,

1 Bacteria are simple, microscopic, vegetable cells, usually very minute, composed of protoplasm with perhaps an enveloping membrane. They multiply often with great rapidity by transverse division or by the formation of spores, the latter being vastly more resistant to destructive influences than the bacteria themselves. According to shape, they are divided into (1) micrococci, round or sphsero bacteria : (2) bacilli, or desmo-bacteria, rodshaped bacteria ; (3) spirilla?, or spirochcstc? , spiral-shaped bacteria. The micrococci of pus occur singly or in irregular clusters called staphylococci, or in chains called streptococci. The forms most frequently found in the pus of acute abscesses are the staphylococcus pyogenes aureus and the streptococcos pyogenes albus. There are a great many other varieties of micrococci, but these are the principal.

16 NOTES OK MATERIA MEDICA.

their action is by the generation of a poison, 1 as in septicaemia. 2 Since the identification of the bacillus of Asiatic cholera, attention has been directed to the alimentary canal as the seat of generation of morbid bacteria. This disease and those of common cholera, yellow fever, dysentery, cholera infantum, etc., are now supposed to be due to the development of bacteria in ,the intestines.

The extraneous or accidental diseases due to the presence in the system of some form of organic life may be divided into two classes, each with its special distinctive marks : (1) the " communicable"; (2) the "non-communicable/'

I. Communicable Diseases. — In this class it is necessary that the disease shall have previously existed as such in an animal body, and its reproduction in the newly infected person be merely a succession of kind. Usually, infected animals communicate the disease to members of the same species, as man to man, but sometimes the disease is conveyed from man to animals and vice versa. The term "communicable " is used advisedly to designate this class of diseases, in preference to the word "contagious/' for the derivation of the latter term conveys the erroneous impression that contact is necessary to the spread of the disease. In former days, this impression was the cause of very dangerous confusion; for if a disease actually spread from one person to another, and yet did not affect those who touched the patient, it was not considered to be contagious, but

1 The word is here used in its stricter meaning. For definition, see ante, p. 12.

2 Septicaemia is a condition of the body produced by the presence of an extremely virulent poison, the product of the growth of certain forms of bacteria, which has a tendency to precipitate the fibrin-producing elements of the blood and to cause the formation of minute emboli. The poison is a definite chemical substance, devoid of life, and consequently producing effects corresponding to the amount absorbed. Septicaemia may be produced by pyaemia.

Pycemia is a condition of the body caused by the presence of morbific bacteria, which are capable of multiplying themselves to such an unlimited extent as to cause death, either physically by interference with the vital functions, or chemically by the production of a virulent poison. Pyaemia is never the result of septicaemia, but may cause it.

due to something in the air, and hence no precautions were taken. On this account, Asiatic cholera, a very communicable but not a contagious disease, carried off thousands upon thousands; but when this disease last appeared in New York, all houses were thoroughly disinfected, and the disease was stamped out with the same directness that firemen stop a conflagration. The virus of this disease (as well as of some others of this class), when it leaves one body, is not immediately ready to enter another, but seems to pass through an intermediate stage upon the surface of the ground or in the air; but it is just as communicable as that of small-pox, and no case of cholera occurs without the infection coming from one who has the disease. The word <e contagion " proposed to define the mode of communication; the term " communicable" does not.

The communicable diseases are subdivided into two classes:

1. Specific. — In this class each disease has its own marked or distinctive symptoms, which are invariably produced in new cases. These cases are the reproduction of the original disease, which is never changed into any other form by pre-existing or intercurrent diseases. Examples: measles, small-pox, scarlet fever, etc.

2. Septic. — The diseases in this subdivision have certain class characters, but it is impossible to predicate the form they will take in every new case. Thus the introduction of erysipelas into a surgical ward is apt to develop pyaemia, while, if introduced into an obstetrical or gynaecological ward, puerperal fever, peritonitis, septicaemia, etc., are induced. The cause of these diseases is one and the same, but its manifestations vary according to the soil on which it falls.

II. Non-communicable Diseases. — These diseases are caused by morbific agents which do not come from an animal body, but have their origin in a place or thing. Many of them are conveyed through the air or water, and these diseases are usually termed malarial; but as the germs are carried as often, if not more often, by water than by air, the term (meaning " bad air") is an unfortunate one; and li miasmatic/' also used to designate them, is equally unfortunate. The germs may also have been 2