Micro-chemistry of poisons, including their physiological, pathological, and legal relations; adapted to the use of the medical jurist, physician, and general chemist

Front matter

I

I

F.O.

Preface

Among the more prominent objects of the present volume are to indicate the limit of the reactions of the different tests that have heretofore been proposed, as also of those now added, for the detection of the principal poisons, and to point out the fallacies attending the reaction of each ; and, also, to apply the microscope, whenever practicable, in determining the nature of the different precipitates, sublimates, etc., and to illustrate these, whenever of any practical utility, by drawings.

Hitherto there have been but comparatively few attempts to show the limit of the reaction of the different tests for poisons, and in these the results have been so discrepant as only to lead to confusion. This discrepancy has arisen chiefly from the fact that the experimentalists have generally failed to state the exact conditions under which the tests were applied. Without such statement, it is obvious that these experiments can have little or no practical value. Thus, for example, if in one instance only one grain of a hundredth solution of the poison be examined, whilst in another one hundred grains of a similar solution be employed, it is obvious that — although the degree of dilution is the same in both — the absolute quantity of the poison present in the latter is one hundred times greater than in the former mixture, vi PREFACE.

and if either will yield a precipitate with a given reagent the quantity produced from the latter will be one hundred times greater than from the former. Similar results would be observed in different quantities of all other solutions, until the degree of dilution exceeded the solubility of the precipitable substance produced by the reaction, when no quantity, however great, of the solution would yield any precipitate whatever.

As illustrative of the discrepancy that has obtained among observers, in regard to the limit of some of the tests that have been examined, may be cited the statements in regard to Reinsch's test for arsenic, the limit of which is placed by one observer at a dilution of 80,000, whilst another fixes it at a dilution of 1,200,000, and others still, place it between these extremes. Admitting that the amount of copper, in regard to surface, employed by these experimentalists, was the same, the results can only be reconciled on the supposition that the quantity of arsenical solution operated upon in the second-named instance was about fourteen times greater than in the first-mentioned ; when, although under very different degrees of dilution, the absolute quantity of arsenic present was about the same in both instances.

Moreover, to give any practical value to investigations of this kind, the experimenter should employ the least quantity of the solution compatible with the application of the test. In most instances, especially with the aid of the microscope, one grain of a given solution of the poison will yield as satisfactory results as a much larger quantity, the only difference being in the amount of precipitate produced. And in all cases, unless the solution be exceedingly concentrated, a given quantity of substance in solution in one grain of fluid will yield very much better results than the same quantity in

PREFACE. vii

a larger amount of liquid, even when in the latter instance the degree of dilution does not exceed the solubility of the precipitable compound produced by the reaction. Throughout the present treatise, the reactions of the liquid tests, with very few exceptions, have been referred to one grain of the poisonous solution. If the operator has sufficient material on hand to permit the examination of larger quantities, his results will, as a general rule, be correspondingly greater than those stated in the text.

Heretofore the microscope has received but little attention as an aid to chemical investigations, yet it is destined to very greatly extend our knowledge in this department of study. As an evidence of the value of micro-chemical analysis, as the Germans first styled it, it is only necessary to state that it enables us by a very few minutes labor to recognise with unerring certainty the reaction of the 100,000th part of a grain of either hydrocyanic acid, mercury, or of arsenic. Many instances might also be cited in which it, with equal facility, enables us to detect the presence of very minute quantities of substances, the true nature of which heretofore could only be determined when present in comparatively large quantity, and by considerable labor.

The microscopic illustrations, all of which are original, were drawn from nature and transferred to steel, by her to whom the work is inscribed. Each was prepared only after an extended examination of the original under the conditions usually present in ordinary analysis: if under these circumstances, the general form of the object illustrated differed from that produced from the substance in its pure state, the difference is noted. In regard to the mechanical execution of the illustrations, we leave it for others to pronounce, simply vni PREFACE.

remarking that the details of many of the figures can only be obtained by means of a lens.

In this connection, the author of the illustrations desires us to acknowledge her obligations and express her thanks to Mr. F. E. Jones, of Cincinnati, through whose kind encouragement she was induced to undertake the execution of the drawings upon steel, for his many valuable suggestions and the interest he manifested in the work during its entire preparation. She would also return her thanks to Mr. J. E. Gavit, of New York, for his kind interest in the undertaking and progress of the work.

In addition to the points now mentioned, those acquainted with the subject will find that in the consideration of nearly every poison, more or less has been added to our knowledge, either in regard to the methods of analysis, the introduction of more delicate or confirmatory tests, or the methods of separation from organic mixtures; especially in regard to the vegetable poisons, many of which can now be recovered from the blood and other organic mixtures with as much certainty as most of the mineral substances. It is rarely that any allusion is made to these contributions, the only object of the author having been to ascertain, according to his experiments, the true value of the statements of others, and add to the common stock of knowledge. In no instance, unless so stated, was (he reaction of a substance deduced from a single experiment, but only from repeated experiments and, when practicable, from different samples of material. If in any instance the author has been misled, no one, tor the cause of science, will rejoice more than he in the demonstration of the error.

It was originally intended to confine the work exclusively to the chemistry of poisons, but in order to adapt it to a

PREFACE. ix

larger class of readers, it was finally determined to also consider their physiological and pathological effects, and point out the treatment proper for each. In the preparation of this part of the work, the principal existing treatises upon the subject, together with many of the medical journals of the day, were freely consulted; but to no systematic works is the author more largely indebted than to the very valuable treatises On Poisons by Drs. Christison and Taylor respectively, especially in the consideration of most of the inorganic poisons. It has been the author's intention, so far as practicable, to give due credit for all cases and matter derived from others. When the original article was not at hand, reference is always made to the work consulted, this rule being rigidly observed throughout the volume.

As within the last few years some two or three different works have appeared illustrating more or less the microscopic appearances of poisons, the author may be permitted to state that the present volume was projected as early as 1857, and a prospectus announcing its plan published in March, 1861, at which time the drawings were about completed.

The work is now presented to the public with the hope that it will not only prove useful to those specially engaged in the chemical investigation of poisons, but also to the Medical Jurist, the Physician, and the General Chemist.

Columbus, Ohio, April, 1867.

Introduction

Micro-Chemistry of Poisons, Definition,

Application of the Microscope, Import of the term Poison, Causes modifying the action of Poisons,

1. Idiosyncrasy,

3. Disease, Classification of Poisons, Sources of Evidence of Poisoning,

I. Evidence from the Symptoms,

1. The Symptoms occur suddenly, .

2. They rapidly run their course, Diseases resembling Poisoning, .

Duties of Medical Attendant,

II. Evidence from Post-mortem Appearances,

Appearances rarely characteristic,

Irritant Poisons, usual effects of,

Narcotic Poisons,

Narcotico-Irritants, .....

Appearances common to Poisoning and Disease,

Redness of the Stomach, ....

Softening of the Stomach, ....

Ulceration and Perforation, ....

Points to be observed in Post-mortem Examinations, III. Evidences from Chemical Analysis,

Importance of Chemical Evidence,

Substances requiring Analysis,

Precautions in -regard to Analyses,

Failure to detect Fatal Quantity,

Value of individual Chemical Tests,

Failure to detect Poison, .

Of Chemical Reagents, .....

Of Chemical Apparatus, .....

Qualifications of the Analyst,

PAGE.

. 33

34 . 34

35 . 35

36 . 37

37 . 39

39 . 39

42 . 43

43 . 44

44 . 45

45 . 45

46 46

TABLE OF CONTENTS.

Chapter I. The Alkalies: Potash, Soda, Ammonia

PAGE.

Genei-al Chemical Nature, . 65

1. Of the Fixed Alkalies, 66

2. Of Ammonia, 66

Nitrate of Potash and other Alkaline Salts, 70

Chemical Properties of the Alkalies, ........ 71

Distinguished from each other, 71

Section I. — Potash. Density of Solutions of Potash, 73

2. Tartaric Acid, and Tartrate of Soda. ...... 76

Spectrum Analysis. ......... 80

Section* II. — Soda.

Density of Solutions of Soda, .......... 83

Coloration of Flame, 84

1. Antimoniate of Potash Test, ....... 84

Behavior with Carbazotic Acid, ....... 87

" " Tartaric " 87

Section II. — Nitric Acid

xiv TABLE OF CONTENTS.

PAGE.

Density- of Solutions of Nitric Acid, 125

2. Gold Test, 127

4. Indigo Test, 129

5. Brucine Test, 131

6. Narcotine, and Iodine Tests, ....... 132

Schseffer's, and Horsley's Tests, ....... 133

From Organic Fabrics, 137

Section III. — Phosphorus

xvin TABLE OF CONTENTS.

PAGE.

Detection after Long Periods, 308

III. Arsenic Acid.

2. Ammonio-Sulphate of Copper, ....... 314

4. Reinsch's Test, 315

5. Ammonio-Sulphate of Magnesia, ....... 316

Other Reactions, .... ..... 317

CHAPTER VI.

MERCURY.

General Properties, 319

Composition, 320

Of Solutions of Corrosive Sublimate, 331

1. Ammonia Test, 331

2. Potash and Soda, 332

5. Chloride of Tin, 336

Vomited Matters, 346

Contents of the Stomacli, :;";

TABLE OF CONTENTS. xix

PAGE.

CHAPTER VII.

LEAD, COPPER, ZINC.

Section I. — Lead. Of Solutions of Acetate of Lead, 360

7. The Alkaline Carbonates, ........ 367

8. Oxalate of Ammonia, ......... 368

9. Zinc Test, 368

The Urine, 372

Section II. — Copper

Sulphate of Copper and Verdigris, . . . . . . .374 xx TABLE OF CONTENTS.

PAGE.

Of Solutions of Salts of Copper, 379

3. Potash and Soda, 382

6. Platinum and Zinc Test, 385

7. Arsenite of Potash, 386

Detection of the Acid, 388

The Urine, 391

Section III. — Zinc. Sulphate of Zinc, 393

Chloride of Zinc, 394

Chemical Properties of Salts of Zinc, 397

When in Solution, 398

7. Phosphate of Soda, 403

Detection of the Acid, 403

TABLE OF CONTENTS.

Part Second. Vegetable Poisons

INTRODUCTION.

PAGE.

General Nature of Vegetable Poisons, 409

Separation from Complex Organic Mixtures, . . . . . . 410

1. Method of Stas, 411

2. Rodgers and Girdwood's Method, ...... 416

3. Method of Uslar and Erdmann, ....... 417

4. Process of Graham and Hofmann, 419

5. Method by Dialysis, 420

Chapter II. Opium And Some Of Its Constituents

I. — Opium.

Physical and Chemical Properties, ........ . 465

II. — Morphine.

Period of Death and Fatal Quantity, 468

Treatment and Post-mortem Appearances, ....... 470

Of Solutions of Salts of Morphine 473

1. Potash and Soda Tests, 473

TABLE OF CONTENTS. xxm

PAGE.

4. Iodic Acid, 476

5. Sesquichloride of Iron, 477

13. Chlorine and Ammonia, 482

Relative Value of the Preceding Tests, 483

III. — Meconic Acid.

1. Sesquichloride of Iron Test, 486

7. Chloride of Calcium, 491

SEPARATION OF MECONIC ACID AND MORPHINE FROM ORGANIC MIXTURES.

Examination for Morphine alone, ...... 499

The Urine, . 503

Quantitative Analysis of Morphine, 504

IV. — Narcotine.

xxiv TABLE OF CONTENTS.

PAGE.

2. Sulphuric Acid and Nitrate of Potash, 508

3. Acetate of Potash, 509

10. Carhazotic Acid, 513

V. — Codeine.

8. Carhazotic Acid, 519

9. Nitric Acid and Potash, 519

VI. — Narceine.

1. Iodine in Iodide of Potassium Test, 522

5. Carhazotic Acid, 524

VII. — Opianyl.

TABLE OF CONTENTS. xxv

PAGE.

1. Iodine in Iodide of Potassium Test, 526

3. Sulphuric Acid and Heatj 527

Chapter III. Nux Vomica, Strychnine, Brucine

I. Nux Vomica.

History and Composition, .......... 529

II. Strychnine.

Of Solutions of Strychnine, ......... 551

2. Color Test, 553

10. Iodohydrargyrate of Potassium, ...... 573 xxvi TABLE OF CONTENTS.

PAGE.

From Nux Vomica. ......... 579

Method by Dialysis. 582

The Blood. 587

III. Brucixe.

2. Nitric Acid and Chloride of Tin Test 597

3. Sulphuric Acid and Nitrate of Potash, 598

Other Reactions, 604

Separation from Organic Mixture?. 604

Chapter IV. Aconitine, Atropine, Daturine

y and Preparation, 606

Chemical Proper! ics, . . . . . . . . . . .614

- ibility

Of Solutions of Ac^nitine, .......... 616

2. Terchloride of Gold Test 617

TABLE OF CONTENTS. xxvii

PAGE.

Fallacies of Preceding Tests, 618

Section II. — Atropine. (Belladonna.)

Of Solutions of Atropine, .......... 629

2. Bromine in Bromohydric Acid Test, 630

Section III. — Daturine. (Stramonium.)

Section I. — Veratrine. (White Hellebore.) Symptoms. — Veratrum Album, ......... 645

Veratrum Viride, ......... 646 xxvin TABLE OF CONTENTS.

PAGE.

Of Solutions of Veratrine, 651

Section II. — Solanine. (Nightshade.) Of Solutions of Solanine, 662

ILLUSTRATIONS UPON STEEL.

Fig.

ee

(i

Et

IE

6,

PLATE I.

Fig. 1. y^g- grain Potash, in the form of nitrate or chloride, -J- Bichloride of Platinum, X 225 diameters.

" 2. j-^-q grain Potash, as nitrate, -\- Tartaric Acid, X 100 diameters.

" 3. ^L. grain Potash, as chloride, -f- Tartrate of Soda, X 80 diameters.

» 4. ^1^ grain Potash, as nitrate, + Carbazotic Acid, X 40 diameters.

« 5. _l_ grain Ammonia, as chloride, -4- Carbazotic Acid, X 40 diameters.

" 6. ^5 grain Soda, -|- Carbazotic Acid, X 40 diameters.

PLATE II.

Fig. 1. ^g- — y^Q- grain Soda, -}- Antimoniate of Potash, X 100 diameters. " 2. ^ grain Soda, -j- Tartaric Acid, X 40 diameters.

" ^. ToVo grain Soda, as chloride, -4- Bichloride of Platinum, X 40 diameters.

" 4. y^-Q grain Sulphuric Acid, -f- Chloride of Barium, X 100 diameters.

" 5. Hydrofluosilicic Acid, + Chloride of Barium, X 100 diameters.

" 0. y-j^ grain Sulphuric Acid, -4- Nitrate of Strontia, X 75 diameters.

PLATE III.

j-ig- grain Hydrochloric Acid, -f- Acetate of Lead, X 40 diameters. 1(f-00 grain Oxalic Acid, on spontaneous evaporation, X 80 diameters, grain Oxalic Acid, -4- Chloride of Calcium, X 225 diameters, grain Oxalic Acid, -4- Chloride of Barium, X 80 diameters. ™- grain Oxalic Acid, -j- Nitrate of Strontia, X 125 diameters, -jig- grain Oxalic Acid, •+ Acetate of Lead, X 80 diameters.

PLATE IV.

Fig. 1. 10oo0 grain Hydrocyanic Acid vapor, -f- Nitrate of Silver, X 222 diameters. " 2. xo-qVoo ST'din Hydrocyanic Acid vapor, -(- Nitrate of Silver, X 125 diameters. " **■ ToVtr grain Phosphoric Acid, -\- Ammonio-Sulphate of Magnesia, X 80

diameters.

" 4. Tartar Emetic, from hot supersaturated solution, X 40 diameters. " 5. Arsenious Acid, sublimed, X 125 diameters.

" ^- To7 grain Arsenious Acid -j- Ammonio-Nitrate of Silver, X 75 diameters.

ILLUSTRATIONS UPON STEEL.

PLATE V.

Fig. 1. ^-ij grain Arsenic Acid, -4- Ammonio- Sulphate of Magnesia, X 75 diameters. 2. Corrosive Sublimate, sublimed, X 40 diameters. " 3. y£j grain Lead, -f- diluted Sulphuric Acid, X 80 diameters. " 4. Tiff grain Lead, -J- diluted Hydrochloric Acid, X 80 diameters. 5. ^-joo grain Lead, -j- Iodide of Potassium, X 80 diameters.

TTToiT grain Zinc, -f- Oxalic Acid, X 80 diameters.

PLATE VI.

Fig. 1. jfe grain Nicotine, -j- Bichloride of Platinum, X 40 diameters 2. j-^q grain Nicotine, -j- Corrosive Sublimate, X 40 diameters.

" 3- totto grain Nicotine, -j- Carbazotic Acid, X 40 diameters.

■ 4. Conine, pure, -j- vapor of Hydrochloric Acid. X 40 diameters.

"' &■ TW grain Conine, -j- Carbazotic Acid, X 40 diameters.

" *>. vbu ?rain Morphine, -j- Potash or Ammonia, X 40 diameters.

PLATE VII.

Tiro" grain Morphine, -f- Iodide of Potassium, X 40 diameters.

Too grain Morphine, -j- Chr ornate of Potash, X 80 diameters.

■j-i^ grain Morphine, -f- Bichloride of Platinum, X 80 diameters.

jfo grain Mbcontc Acid. -f- Chloride of Barium, X §0 diameters.

yi^ grain Meconic Acid, -\- Hydrochloric Acid, X 75 diameters.

yi^ grain Meconic Acid, -f- Ferricyanide of Potassium. X 40 diameters.

Fig.

..

.

..

..

it

PLATE VIII.

Fig. 1. yiff grain Meconic Acid, -4- Chloride of Calcium, X 75 diameters. 2. xo^otj grain Narcotine. -f- Potash or Ammonia. X 40 diameters. " ^. tto grain Narcotine, -f- Acetate of Potash, X 80 diameters. • 4. jiy grain Codeine, -}- Iodine in Iodide of Potassium, X 40 diameters.

rhi grain Iodide of Codeine, from alcoholic solution, X 75 diameters. 6. yi^ grain Codeine, -\- Sulphocyanide of Potassium, X 40 diameters.

PLATE IX.

Fig. 1. j\T) grain Codeine, -j- Bichromate of Potash, X 40 diameters. 2. yJj grain Codeine, -j- Iodide of Potassium, X 40 diameters. " <*. id ob gra>" Nabceine, -7- Iodine in Iodide of Potassium, X 40 diameters. " *• 000" gra'n N u:' I :-1- 4" Bichromate of Potash, X 40 diameters.

oio" grain Opianyl, -\- Iodine in Iodide of Potassium, X 40 diameters. y^7 grain Opianyl. -f- Bromine in Bromohydric Acid, X 40 diameters.

ILLUSTRATIONS UPON STEEL.

PLATE X.

Fig. 1. yig- grain Strychnine, + Potash or Ammonia, X 40 diameters. " 2. j-^-q grain Strychnine, -f- Sulphocyanide of Potassium, X 40 diameters. " 3. 5^0 grain Strychnine, -j- Bichromate of Potash, X 40 diameters.

" 4. 251Q0 grain Strychnine, -f- Bichromate of Potash, X 80 diameters. " 5, i grain Strychnine, -f- Chloride of Gold, X 40 diameters.

" 6. TToo grain Strychnine, -j- Bichloride of Platinum, X 40 diameters.

PLATE XL

Fig. 1. jJp grain Strychnine, -)- Carbazotic Acid, X 80 diameters.

" 2. T-L grain Strychnine, -\- Corrosive Sublimate, X 40 diameters.

" 3. ^i- grain Strychnine, -f- Ferricyanide of Potassium, X 40 diameters.

" 4. io a o grain Strychnine, -\- Iodine in Iodide of Potassium, X 80 diameters.

" *>. y^q grain Brucine, -\- Potash or Ammonia, X 40 diameters.

" 6. lio grain Brucine, -f- Sulphocyanide of Potassium, X 40 diameters.

PLATE XII.

Fig. 1. T^o grain Brucine, -\- Bichromate of Potash, X 80 diameters.

2. 1Q100 grain Brucine, -|- Bichloride of Platinum, X 40 diameters.

3. j-Jq- grain Brucine, -\- Ferricyanide of Potassium, X 40 diameters.

4. y^q grain Atropine, + Potash or Ammonia, X 75 diameters.

5. y^-q grain Atropine, -\- Bromine in Bromohydric Acid, X 75 diameters.

6. xFffTo grain Atropine, -f- Bromine in Bromohydric Acid, X 125 diameters.

PLATE XIII.

Fig. 1. j-^-q grain Atropine, 4- Carbazotic Acid, X 80 diameters.

" 2. y^q grain Atropine, -j- Chloride of Gold, X 80 diameters.

" ^- Tiro grain Veratrine, -\- Chloride of Gold, X 40 diameters.

" 4. y^q grain Veratrine, -{- Bromine in Bromohydric Acid, X 80 diameters.

" 5. Solanine, from alcoholic solution, X 80 diameters.

" 6. j-jj-Q grain Solanine, as sulphate, on spontaneous evaporation, X 80 diameters.

MICRO-CHEMISTRY OF POISONS.

INTRODUCTION.

DEFINITION ; APPLICATION OF THE MICROSCOPE IMPORT OF THE

TERM POISON ; MODIFYING CIRCUMSTANCES CLASSIFICATION

OF POISONS SOURCES OF EVIDENCE OF POISONING:

EVIDENCE FROM SYMPTOMS FROM POST-MORTEM

APPEARANCES FROM CHEMICAL ANALYSIS.

By the term Micro-Chemistry of Poisons, we understand the study of the chemical properties of poisons as revealed by the aid of the microscope. Although the scope of the present work is not lhnited to this department of the subject, vet as that branch of the science forms a main element of the treatise, we have designated it by that title.

The instrument requisite for investigations of this kind may be comparatively simple; and but little accessory apparatus will be required. The stage of the instrument shotdd be sufficiently large to receive a watch-glass having a diameter of not less than two inches. Object-glasses of only low power are usually required. Very often an amplification of from thirty to forty diameters will answer the purpose best, but more frequently, perhaps, a power of about seventy-five will be the most satisfactory, while in some few instances an amplification of about two hundred and fifty will be required. The objectives best suited for these powers are the inch and a half, two-thirds inch, and one-fifth inch, respectively. In these investigations, as in all others with the microscope, the lowest amplification that will reveal the true character of the object examined, will be the most satisfactory. A polarizing apparatus will sometimes be necessary to determine the true nature of an object; and in some instances a micrometer will be found useful to ascertain the absolute size of the object.

In applying- the microscope to the examination of the result of a chemical reagent upon a suspected solution, a single drop of the liquid, placed in a watch-glass or upon a glass slide, is treated with a very small quantity of the reagent, added by means of a pipette, and the mixture, with as little agitation as possible, transferred to the stage of the instrument. If, as is sometimes the case, the crystalline deposit produced by the reagent be readily broken up by agitation, the watch-glass containing the drop of fluid to be examined, is placed on the stage of the instrument before the addition of the reagent. In many instances, as will be noticed hereafter, the formation of a precipitate is much facilitated by stirring the mixture with a glass rod. Should the mixture evolve fumes injurious to the object-glass, a flat watch-glass having a ground edge is selected, and this covered by a piece of very thin glass. Any special directions in regard to the use of this instrument, will be pointed out hereafter, as occasion may require.

A Poison is any substance which, when introduced into the body and being absorbed, or by its direct chemical action, or when applied externally and entering the circulation, is capable of producing deleterious effects. There is no doubt but all poisons are to a greater or less extent absorbed into the circulation. In fact, with most of them this is certainly a condition essential to the production of their effects; yet it would appear that in the action of some substances, which produce local chemical changes, death, in some instances at least, can only be referred to the effects of the changes thus produced. The mineral acids and caustic alkalies are the principal poisons which have a direct chemical action upon the parts with which tiny are broughl in contact. This action is due to a mutual affinity existing between the agenl and the tissue. In this respect, the action of the.se substances differs from that of certain heated liquids, such as boiling water, which are inert at ordinary temperatures, but which, simply on account of their

CAUSES MODIFYING THE ACTION OF POISONS. 35

condition, induce a chemical change in the part to which they are applied, without themselves being chemically concerned in the change. When applied externally, some poisons are absorbed by simply being brought in contact "with the unbroken skin; whilst others do not enter the circulation unless applied to an abraded or wounded surface.

Poisons differ greatly in regard to the quantity necessary to prove injurious. Thus the fiftieth part of a grain of aconitine has seriously endangered the life of an adult, while on the other hand, an ounce of sulphate of magnesia may generally be administered with impunity; yet in large quantities the latter substance has in several instances caused death, and is strictly a poison, although not commonly reputed as such. As yet we know of no substance that is poisonous in all proportions. Any of the most powerful poisons may be administered in certain quantities without producing any appreciable effect, and most of them may be so employed as to constitute valuable remedial agents.

In medico-legal inquiries, the leading idea connected with the term poison, is whether the given results are directly traceable to the substance and the intention with which it was employed.

Poisons not only differ from each other in regard to the quantity necessary to destroy life, but the effects of the same substance may be much modified by circumstances, and even substances which to most persons are harmless may, on account of certain peculiarities of constitution, produce deleterious effects.

Causes which modify the effects of Poisons. — Among the causes which may modify the effects of poisons, may, in this connection, be mentioned Idiosyncrasy, Habit, and a Diseased State of the System.

1. Idiosyncrasy, or a peculiarity of constitution, may variriously modify the effects of substances. Thus to some persons ordinary medicinal doses of certain drugs, such as opium or mercury, produce violent symptoms, and even death. In other instances, substances which to most persons are harmless, and even ordinary articles of food, produce symptoms of irritant

3* poisoning. This has been observed in the eating of certain kinds of fish, honey, pork, veal, and mutton. In still another form of idiosyncrasy, there is a diminished susceptibility to the action of certain substances, which to most persons are active poisons. This peculiarity of constitution is very rare, and is most generally observed in regard to the action of mercury and opium. Dr. Christison relates an instance, in which a gentleman, unaccustomed to the use of opium, took without injury nearly an ounce of good laudanum.

2. Habit may render certain poisons harmless in doses, which to most persons would prove rapidly fatal. The influence of habit is daily seen in the use of opium, tobacco, and alcohol; and it is well known that certain other agents when administered medicinally, in frequently-repeated doses, after a time lose their ordinary effects. Persons accustomed to the use of opium, have taken daily, for long periods together, quantities of laudanum that would prove fatal to several persons unaccustomed to its use. Although this influence has principally been observed, as remarked by Dr. Christison, in regard to the action of certain organic poisons, especially such as act on the brain and nervous system; yet it seems now to be fully established that certain persons in Styria accustom themselves even to the eating of arsenic in doses of several grains daily, and continue the practice for many years without experiencing any of the usual effects of the poison. The statements formerly made by Dr. Tschudi and others in regard to the existence of this practice, have been discredited by most writers on toxicology ; but the accounts more recently published by Dr. Roscoe, as quoted by Dr. Taylor (Med. Jur., Amer. ed., 1861, p. 693), and the direct observations of Dr. Maclagan, of Edinburgh (Chemical News, London, July, 1865, p. 36), while on a visit to Styria, seem to leave no doubt whatever of its existence. In one of the cases observed by Dr. Maclagan, the individual, a muscular young man, aged twenty-six years, swallowed in connection with a very small piece of bread, five grains of genuine powdered arsenious acid, or white arsenic, which he stated was about the quantity he was in the habit of taking twice a week. In the urine passed by this individual

CLASSIFICATION OF POISONS. 37

two hours afterward, as also in that passed after twenty-sis hours, Dr. Maclagan detected a very notable quantity of arsenic. It is but proper to observe, that the experience of most medical practitioners in the use of this substance, does not accord with the results of this Styrian practice.

3. Disease. — In certain diseased conditions of the system, there is a diminished susceptibility to the action of certain poisons; whilst in others, there is an increased susceptibility, even to the action of the same substance. Thus in tetanus, hydrophobia, mania, and delirium tremens, quantities of opium, which in ordinary states of the system would be fatal, may often be administered with beneficial effects. In a case of tetanus related by Dr. Watson (Practice of Physic), something over four ounces of laudanum were taken on an average daily, for twenty days; after which the patient recovered. The same writer quotes another instance of the same affection, in which an ounce of solid opium was taken, in divided doses, daily, for twenty-two days. So also, in inflammation of the lungs, enormous doses of tartar emetic have been given with advantage. On the other hand, in cases in which there is a predisposition to apoplexy, an ordinary dose of opium may cause death. In like manner, in certain diseases, there is an increased susceptibility to the action of mercury and other mineral substances.

Classification of Poisons. — Most recent writers on this subject have adopted the arrangement of poisons, according to the symptoms they produce, into three classes, namely, Irritants, Narcotics, and Narcotico-Irritants. Since, however, there are many poisons, the effects of which are subject to great variation, and others which according to their ordinary effects, might with equal propriety be placed in one or another of these classes, this classification is open to objection; nevertheless, it is, perhaps, the best, for practical purposes, yet proposed.

Irritant Poisons, as a class, produce irritation and inflammation of the stomach and bowels, attended or followed by intense pain in these parts, tenderness of the abdomen, and violent vomiting and purging, the matters evacuated being often tinged with blood. Some of the members of this class, such as the mineral acids and caustic alkalies, also possess corrosive properties, and accordingly occasion, in addition to the effects just mentioned, more or less disorganization of the mouth, throat, oesophagus, and stomach. The action of these substances, if not too dilute, is immediate, and is attended with a sense of burning heat in the parts with which they come in contact. When highly diluted, any of the corrosive poisons may act by simply inducing irritation and inflammation.