Chapter XIV: Part II: I.--Definition of Poison (1)

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§ 14. The term “_Poison_” may be considered first in its legal, as distinct from its scientific, aspect.

_The legal definition_ of “poison” is to be gathered from the various statute-books of civilised nations.

The English law enacts that: “Whoever shall administer, or cause to be administered to, or taken by any person, any poison or other destructive thing, with intent to commit murder, shall be guilty of felony.”

Further, by the Criminal Consolidation Act, 1861: “Whosoever shall, by any other means other than those specified in any of the preceding sections of this Act, attempt to commit murder, shall be guilty of felony.”

It is therefore evident that, by implication, the English law defines a poison to be a destructive thing administered to, or taken by, a person, and it must necessarily include, not only poisons which act on account of their inherent chemical and other properties after absorption into the blood, but mechanical irritants, and also specifically-tainted fluids. Should, for example, a person give to another milk, or other fluid, knowing, at the same time, that such fluid is contaminated by the specific poison of scarlet fever, typhoid, or any serious malady capable of being thus conveyed, I believe that such an offence could be brought under the first of the sections quoted. In fine, the words “_destructive thing_” are widely applicable, and may be extended to any substance, gaseous, liquid, or solid, living or dead, which, if capable at all of being taken within the body, may injure or destroy life. According to this view, the legal idea of “poison” would include such matters as boiling water, molten lead, specifically-infected fluids, the flesh of animals dying of diseases which may be communicable to man, powdered glass, diamond dust, &c. Evidence must, however, be given of guilty intent.

The words, “administered to or taken by,” imply obviously that the framers of the older statute considered the mouth as the only portal of entrance for criminal poisoning, but the present law effectually guards against any attempt to commit murder, no matter by what means. There is thus ample provision for all the strange ways by which poison has been introduced into the system, whether it be by the ear, nose, brain, rectum, vagina, or any other conceivable way, so that, to borrow the words of Mr. Greaves (_Notes on Criminal Law Consolidation_), “the malicious may rest satisfied that every attempt to murder which their perverted ingenuity may devise, or their fiendish malignity suggest, will fall within some clause of this Act, and may be visited with penal servitude for life.”

Since poison is often exhibited, not for the purpose of taking life, but from various motives, and to accomplish various ends--as, for example, to narcotise the robber’s victim (this especially in the East), to quiet children, to create love in the opposite sex (love philters), to detect the secret sipper by suitably preparing the wine, to expel the inconvenient fruit of illicit affection, to cure inebriety by polluting the drunkard’s drink with antimony, and, finally, to satisfy an aimless spirit of mere wantonness and wickedness, the English law enacts “that whosoever shall unlawfully or maliciously administer to, or cause to be taken by, any other person, any poison or other destructive or noxious thing, so as thereby to endanger the life of such person, or so as thereby to inflict upon such person any grievous bodily harm, shall be guilty of felony.”

There is also a special provision, framed, evidently, with reference to volatile and stupefying poisons, such as chloroform, tetrachloride of carbon, &c.:--

“Whoever shall unlawfully apply, or administer to, or cause to be taken by any person, any chloroform, laudanum, or other stupefying or overpowering drug, matter, or thing, with intent, in any such case, thereby to enable himself or any other person to commit, or with intent, &c., to assist any other person in committing, any indictable offence, shall be guilty of felony.”

§ 15. The German statute, as with successive amendments it now stands, enacts as follows:[27]--

[27] “Wer vorsätzlich einem Andern, um dessen Gesundheit zu beschädigen, Gift oder andere Stoffe beibringt, welche die Gesundheit zu zerstören geeignet sind, wird mit Zuchthaus von zwei bis zu zehn Jahren bestraft.

“Ist durch die Handlung eine schwere Körperverletzung verursacht worden, so ist auf Zuchthaus nicht unter fünf Jahren, und wenn durch die Handlung der Tod verursacht worden, auf Zuchthaus nicht unter zehn Jahren oder auf lebenslängliches Zuchthaus zu erkennen.

“Ist die vorsätzliche rechtswidrige Handlung des Gift--&c.,--Beibringens auf das ‘Tödten’ gerichtet, soll also durch dieselbe gewollter Weise der Tod eines Anderen herbeigeführt werden, so kommt in betracht: Wer vorsätzlich einen Menschen tödtet, wird, wenn er die Tödtung mit Ueberlegung ausgeführt hat, wegen Mordes mit dem Tode bestraft.”

“Whoever wilfully administers (_beibringt_) to a person, for the purpose of injuring health, poison, or any other substance having the property of injuring health, will be punished by from two to ten years’ imprisonment.

“If by such act a serious bodily injury is caused, the imprisonment is not to be less than five years; if death is the result, the imprisonment is to be not under ten years or for life.

“If the death is wilfully caused by poison, it comes under the general law: ‘Whoever wilfully kills a man, and if the killing is premeditated, is on account of murder punishable with death.’”

The French law runs thus (Art. 301, _Penal Code_):--“Every attempt on the life of a person, by the effect of substances which may cause death, more or less suddenly, in whatever manner these substances may have been employed or administered, and whatever may have been the results, is called poisoning.”[28]

[28] “Est qualifié _empoisonnement_--tout attentat à la vie d’une personne par l’effet de substances qui peuvent donner la mort plus ou moins promptement, de quelque manière que ces substances aient été employées ou administrées, et quelles qu’en aient été les suites.”--Art. 301, _Penal Code_.

There is also a penalty provided against any one who “shall have occasioned the illness or incapacity for personal work of another, by the voluntary administration, in any manner whatever, of substances which, without being of a nature to cause death, are injurious to health.”[29]

[29] “Celui qui aura occasionné à autrui une maladie ou incapacité de travail personnel en lui administrant volontairement, de quelque manière que ce soit, des substances qui, sans être de nature à donner la mort, sont nuisibles à la santé.”--Art. 317, _Penal Code_.

§ 16. =Scientific Definition of a Poison.=--A true scientific definition of a poison must exclude all those substances which act mechanically,--the physical influences of heat, light, and electricity; and parasitic diseases, whether caused by the growth of fungus, or the invasion of an organism by animal parasites, as, for example, “trichinosis,” which are not, so far as we know, associated with any poisonous product excreted by the parasite;--on the other hand, it is now recognised that pathogenic micro-organisms develop poisons, and the symptoms of all true infections are but the effects of “toxines.” The definition of poison, in a scientific sense, should be broad enough to comprehend not only the human race, but the dual world of life, both animal and vegetable.

Husemann and Kobert are almost the only writers on poisons who have attempted, with more or less success, to define poison by a generalisation, keeping in view the exclusion of the matters enumerated. Husemann says--“We define poisons as such inorganic, or organic substances as are in part capable of artificial preparation, in part existing, ready-formed, in the animal or vegetable kingdom, which, without being able to reproduce themselves, through the chemical nature of their molecules under certain conditions, change in the healthy organism the form and general relationship of the organic parts, and, through annihilation of organs, or destruction of their functions, injure health, or, under certain conditions, destroy life.” Kobert says:--“Poisons are organic or inorganic unorganised substances originating in the organism itself, or introduced into the organism, either artificially prepared, or ready formed in nature, which through their chemical properties, under certain conditions, so influence the organs of living beings, that the health of these beings is seriously influenced temporarily or permanently.”

In the first edition of this work I made an attempt to define a poison thus:--_A substance of definite chemical composition, whether mineral or organic, may be called a poison, if it is capable of being taken into any living organism, and causes, by its own inherent chemical nature, impairment or destruction of function_. I prefer this definition to Kobert’s, and believe that it fairly agrees with what we know of poisons.

II.--Classification of Poisons.

§ 17. At some future time, with a more intimate knowledge of the way in which each poison acts upon the various forms of animal and vegetable life, it may be possible to give a truly scientific and philosophical classification of poisons--one based neither upon symptoms, upon local effects, nor upon chemical structure, but upon a collation and comparison of all the properties of a poison, whether chemical, physical, or physiological. No perfect systematic arrangement is at present attainable: we are either compelled to omit all classification, or else to arrange poisons with a view to practical utility merely.

From the latter point of view, an arrangement simply according to the most prominent symptoms is a good one, and, without doubt, an assistance to the medical man summoned in haste to a case of real or suspected poisoning. Indeed, under such circumstances, a scheme somewhat similar to the following, probably occurs to every one versed in toxicology:--

A. POISONS CAUSING DEATH IMMEDIATELY, OR IN A FEW MINUTES.

There are but few poisons which destroy life in a few minutes. Omitting the strong mineral acids, carbon monoxide, carbon dioxide, with the irrespirable gases,--_Prussic acid_, _the cyanides_, _oxalic acid_, and occasionally _strychnine_, are the chief poisons coming under this head.

B. IRRITANT POISONS (symptoms mainly pain, vomiting, and purging).

_Arsenic_, _antimony_, _phosphorus_, _cantharides_, _savin_, _ergot_, _digitalis_, _colchicum_, _zinc_, _mercury_, _lead_, _copper_, _silver_, _iron_, _baryta_, _chrome_, _yew_, _laburnum_, _and putrid animal substances._

C. IRRITANT AND NARCOTIC POISONS (symptoms those of an irritant nature, with the addition of more or less pronounced cerebral indications).

To this class more especially belong _oxalic acid_ and _the oxalates_, with several poisons belonging to the purely narcotic class, but which produce occasionally irritant effects.

D. POISONS MORE ESPECIALLY AFFECTING THE NERVOUS SYSTEM.

1. NARCOTICS (chief symptom insensibility, which may be preceded by more or less cerebral excitement): _Opium_, _Chloral_, _Chloroform_.

2. DELIRIANTS (delirium for the most part a prominent symptom): _Belladonna_, _hyoscyamus_, _stramonium_, _with others of the Solanaceæ_, to which may be added--_poisonous fungi_, _Indian hemp_, _lolium temulentum_, _œnanthe crocata_, and _camphor_.

3. CONVULSIVES.--Almost every poison has been known to produce convulsive effects, but the only true convulsive poisons are the _alkaloids of the strychnos class_.

4. COMPLEX NERVOUS PHENOMENA: _Aconite_, _digitalis_, _hemlock_, _calabar bean_, _tobacco_, _lobelia inflata_, and _curara_.

* * * * *

§ 18. KOBERT’S CLASSIFICATION.--The latest authority on poisons--Kobert--has classified poisons according to the following scheme:--

I. POISONS WHICH CAUSE COARSE ANATOMICAL CHANGES OF THE ORGANS.

A. Those which specially irritate the part to which they are
applied.

1. _Acids._

2. _Caustic alkalies._

3. _Caustic salts_, especially those of the heavy metals.

4. Locally irritating organic substances which neither can be
classified as corrosive acids nor alkalies, nor as corrosive salts;
such are:--_cantharidine_, _phrynine_, and others in the animal
kingdom, _croton oil_ and _savin_ in the vegetable kingdom. Locally
irritating colours, such as the _aniline dyes_.

5. Gases and vapours which cause local irritation when breathed,
such as _ammonia_, _chlorine_, _iodine_, _bromine_, and _sulphur
dioxide_.

B. Those which have but little effect locally, but change
anatomically other parts of the body; such as _lead_, _phosphorus_,
and others.

II. BLOOD POISONS.

1. Blood poisons interfering with the circulation in a purely
physical manner, such as _peroxide of hydrogen_, _ricine_, _abrine_.

2. Poisons which have the property of dissolving the red blood
corpuscle, such as the _saponins_.

3. Poisons which, with or without primary solution of the red blood
corpuscles, produce in the blood methæmoglobin; such as _potassic
chlorate_, _hydrazine_, _nitrobenzene_, _aniline_, _picric acid_,
_carbon disulphide_.

4. Poisons having a peculiar action on the colouring matter of the
blood, or on its decomposition products, such as _hydric sulphide_,
_hydric cyanide_, and the _cyanides_ and _carbon monoxide_.

III. POISONS WHICH KILL WITHOUT THE PRODUCTION OF COARSE ANATOMICAL CHANGE.

1. Poisons affecting the cerebro-spinal system; such as
_chloroform_, _ether_, _nitrous oxide_, _alcohol_, _chloral_,
_cocaine_, _atropine_, _morphine_, _nicotine_, _coniine_,
_aconitine_, _strychnine_, _curarine_, and others.

2. Heart Poisons; such as, _digitalis_, _helleborin_, _muscarine_.

IV. POISONOUS PRODUCTS OF TISSUE CHANGE.

1. Poisonous albumin.

2. Poisons developed in food.

3. Auto-poisoning, _e.g._ uræmia, glycosuria, oxaluria.

4. The more important products of tissue change; such as, _fatty
acids_, _oxyacids_, _amido-fatty acids_, _amines_, _diamines_, and
_ptomaines_.

* * * * *

§ 19. I have preferred an arrangement which, as far as possible, follows the order in which a chemical expert would search for an unknown poison--hence an arrangement partly chemical and partly symptomatic. First the chief gases which figure in the mortality statistics are treated, and then follow in order other poisons.

A chemist, given a liquid to examine, would naturally test first its reaction, and, if strongly alkaline or strongly acid, would at once direct his attention to the mineral acids or to the alkalies. In other cases, he would proceed to separate volatile matters from those that were fixed, lest substances such as prussic acid, chloroform, alcohol, and phosphorus be dissipated or destroyed by his subsequent operations.

Distillation over, the alkaloids, glucosides, and their allies would next be naturally sought, since they can be extracted by alcoholic and ethereal solvents in such a manner as in no way to interfere with an _after_-search for metals.

The metals are last in the list, because by suitable treatment, after all organic substances are destroyed, either by actual fire or powerful chemical agencies, even the volatile metals may be recovered. The metals are arranged very nearly in the same order as that in which they would be separated from a solution--viz., according to their behaviour to hydric and ammoniac sulphides.

There are a few poisons, of course, such as the oxalates of the alkalies, which might be overlooked, unless sought for specially; but it is hoped that this is no valid objection to the arrangement suggested, which, in greater detail, is as follows:--

A.--POISONOUS GASES.

1. Carbon monoxide.
2. Chlorine.
3. Hydric sulphide.

B.--ACIDS AND ALKALIES.

1. Sulphuric acid.
2. Hydrochloric acid.
3. Nitric acid.
4. Potash.
5. Soda.
6. Ammonia.
7. Neutral sodium, potassium, and ammonium salts.

In nearly all cases of death from any of the above, the analyst, from the symptoms observed during life, from the surrounding circumstances, and from the pathological appearances and evident chemical reactions of the fluids submitted, is put at once on the right track, and has no difficulty in obtaining decided results.

C.--POISONOUS SUBSTANCES CAPABLE OF BEING SEPARATED BY DISTILLATION FROM EITHER NEUTRAL OR ACID LIQUIDS.

1. Hydrocarbons.
2. Camphor.
3. Alcohols.
4. Amyl-nitrite.
5. Chloroform and other anæsthetics.
6. Carbon disulphide.
7. Carbolic acid.
8. Nitro-benzene.
9. Prussic acid.
10. Phosphorus.

The volatile alkaloids, which may also be readily distilled by strongly alkalising the fluid, because they admit of a rather different mode of treatment, are not included in this class.

D.--ALKALOIDS AND POISONOUS VEGETABLE PRINCIPLES SEPARATED FOR THE MOST PART BY ALCOHOLIC SOLVENTS.

DIVISION I.--VEGETABLE ALKALOIDS.

1. Liquid volatile alkaloids, alkaloids of hemlock, nicotine,
piturie, sparteine, aniline.
2. The opium group of alkaloids.
3. The strychnine or tetanic group of alkaloids--strychnine, brucine,
igasurine.
4. The aconite group of alkaloids.
5. The mydriatic group of alkaloids--atropine, hyoscyamine, solanin,
cytisine.
6. The alkaloids of the veratrines.
7. Physostigmine.
8. Pilocarpine.
9. Taxine.
10. Curarine.
11. Colchicin.
12. Muscarine and the active principles of certain fungi.

There would, perhaps, have been an advantage in arranging several of the individual members somewhat differently--_e.g._, a group might be made of poisons which, like pilocarpine and muscarine, are antagonistic to atropine; and another group suggests itself, the physiological action of which is the opposite of the strychnos class; solanin (although classed as a mydriatic, and put near to atropine) has much of the nature of a glucoside, and the same may be said of colchicin; so that, if the classification were made solely on chemical grounds, solanin would have followed colchicin, and thus have marked the transition from the alkaloids to the glucosides.

DIVISION II.--GLUCOSIDES.

1. The digitalis group.
2. Other poisonous glucosides acting on the heart.
3. Saponin.

The glucosides, when fairly pure, are easily recognised; they are destitute of nitrogen, neutral in reaction, and split up into sugar and other compounds when submitted to the action of saponifying agents, such as boiling with dilute mineral acids.

DIVISION III.--CERTAIN POISONOUS ANHYDRIDES OF THE ORGANIC ACIDS.

1. Santonin.
2. Mezereon.

It is probable that this class will in a few years be extended, for several other organic anitrogenous poisons exist, which, when better known, will most likely prove to be anhydrides.

DIVISION IV.--VARIOUS VEGETABLE POISONOUS PRINCIPLES NOT ADMITTING OF CLASSIFICATION UNDER THE PREVIOUS THREE DIVISIONS.

Ergot, picrotoxin, the poison of _Illicium religiosum_, cicutoxin, _Æthusa cynapium_, _Œnanthe crocata_, croton oil, savin oil, the toxalbumins of castor oil and _Abrus_.

The above division groups together various miscellaneous toxic principles, none of which can at present be satisfactorily classified.

E.--POISONS DERIVED FROM LIVING OR DEAD ANIMAL SUBSTANCES.

DIVISION I.--POISONS SECRETED BY THE LIVING.

1. Poisonous amphibia.
2. Poison of the scorpion.
3. Poisonous fish.
4. Poisonous insects--spiders, wasps, bees, beetles, &c.
5. Snake poison.

DIVISION II.--POISONS FORMED IN DEAD ANIMAL MATTERS.

1. Ptomaines.
2. Poisoning by putrid or changed foods--sausage poisoning.

F.--THE OXALIC ACID GROUP.

G.--INORGANIC POISONS.

DIVISION I.--PRECIPITATED FROM A HYDROCHLORIC ACID SOLUTION BY HYDRIC SULPHIDE--PRECIPITATE, YELLOW OR ORANGE.

Arsenic, antimony, cadmium.

DIVISION II.--PRECIPITATED BY HYDRIC SULPHIDE IN HYDROCHLORIC ACID SOLUTION--BLACK.

Lead, copper, bismuth, silver, mercury.

DIVISION III.--PRECIPITATED FROM A NEUTRAL SOLUTION BY HYDRIC SULPHIDE.

Zinc, nickel, cobalt.

DIVISION IV.--PRECIPITATED BY AMMONIA SULPHIDE.

Iron, chromium, thallium, aluminium.

DIVISION V.--ALKALINE EARTHS.

Barium.

III.--Statistics.

§ 20. The number of deaths from poison (whether accidental, suicidal, or homicidal), as compared with other forms of violent, as well as natural deaths, possesses no small interest; and this is more especially true when the statistics are studied in a comparative manner, and town be compared with town, country with country.

The greater the development of commercial industries (especially those necessitating the use or manufacture of powerful chemical agencies), the more likely are accidents from poisons to occur. It may also be stated, further, that the higher the mental development of a nation, the more likely are its homicides to be caused by subtle poison--its suicides by the euthanasia of chloral, morphine, or hemlock.

Other influences causing local diversity in the kind and frequency of poisoning, are those of race, of religion, of age and sex, and the mental stress concomitant with sudden political and social changes.

In the ten years from 1883-1892, there appear to have died from poison, in England and Wales, 6616 persons, as shown in the following tables:--

DEATHS FROM POISON IN ENGLAND AND WALES DURING THE TEN YEARS 1883-92.

+----------------------------+---------+---------+---------+---------+
| |Accident | | | |
| | or | | | |
| | Negli- |Suicide. | Murder. | Total. |
| | gence. | | | | | | |
+----------------------------+----+----+----+----+----+----+----+----+
| | M. | F. | M. | F. | M. | F. | M. | F. |
| | | | | | | | | |
| METALS. | | | | | | | | |
| | | | | | | | | |
|Arsenic, | 37| 14| 37| 20| 1| 1| 75| 35|
|Antimony, | 3| ...| 1| 2| ...| ...| 4| 2|
|Copper, | 4| 1| 2| 1| ...| ...| 6| 2|
|Lead, | 831| 209| 1| 2| ...| ...| 832| 211|
|Silver Nitrate, | 1| ...| ...| ...| ...| ...| 1| ...|
|Zinc Chloride (or Sulphate),| 7| ...| 4| ...| ...| ...| 11| ...|
|Mercury, | 22| 11| 16| 8| 2| 1| 40| 20|
|Chromic Acid, | 1| ...| ...| ...| ...| ...| 1| ...|
|Iron Perchloride, | ...| ...| ...| 1| ...| ...| ...| 1|
| | | | | | | | | |
| ALKALINE EARTHS. | | | | | | | | |
| | | | | | | | | |
|Lime, | 2| ...| ...| 1| ...| ...| 2| 1|
|Barium Chloride, | 1| ...| ...| ...| ...| ...| 1| ...|
| | | | | | | | | |
| THE ALKALIES AND THEIR | | | | | | | | |
| SALTS. | | | | | | | | |
| | | | | | | | | |
|Ammonia, | 39| 25| 18| 16| ...| ...| 57| 41|
|Caustic Soda, | 3| 4| ...| 1| ...| ...| 3| 5|
| „ Potash, | 8| 10| 1| ...| ...| ...| 9| 10|
|Potassic Chlorate, | 1| ...| ...| ...| ...| ...| 1| ...|
| „ Bichromate, | 2| 2| 7| 3| ...| ...| 9| 5|
| „ Bromide, | 1| ...| ...| ...| ...| ...| 1| ...|
| „ Binoxalate | | | | | | | | |
| (Sorrel), | 1| 3| 1| 4| ...| ...| 2| 7|
| | | | | | | | | |
| ACIDS. | | | | | | | | |
| | | | | | | | | |
|Sulphuric Acid, | 30| 9| 29| 24| 1| ...| 60| 33|
|Nitric „ | 18| 7| 18| 9| ...| ...| 36| 16|
|Hydrochloric Acid, | 48| 18| 83| 55| ...| ...| 131| 73|
|Oxalic „ | 17| 6| 114| 86| ...| ...| 131| 92|
|Tartaric „ | ...| 1| ...| ...| ...| ...| ...| 1|
|Acetic „ | 4| 3| ...| 2| ...| ...| 4| 5|
|Carbolic „ | 169| 101| 219| 271| ...| 1| 388| 373|
|Hydrofluoric „ | ...| ...| ...| 1| ...| ...| ...| 1|
|Phosphorus (including | | | | | | | | |
|Lucifer matches), | 24| 47| 28| 56| ...| ...| 52| 103|
|Iodine, | 6| 7| 1| 1| ...| ...| 7| 8|
| | | | | | | | | |
| VOLATILE LIQUIDS. | | | | | | | | |
| | | | | | | | | |
|Paraffin (Petroleum), | 9| 2| 1| ...| ...| ...| 10| 2|
|Benzoline, | 3| 2| ...| 1| ...| ...| 3| 3|
|Naphtha, | 1| ...| ...| ...| ...| ...| 1| ...|
|Carbon Bisulphide, | ...| ...| 1| ...| ...| ...| 1| ...|
|Turpentine, | 5| 1| ...| 3| ...| ...| 5| 4|
|Methylated Spirit, | ...| 2| 1| 2| ...| ...| 1| 4|
|Alcohol, | 81| 24| 1| 2| ...| ...| 82| 26|
|Chloroform, | 57| 41| 9| 5| 1| ...| 67| 46|
|Ether, | 5| 2| ...| ...| ...| ...| 5| 2|
|Spt. Etheris Nitrosi, | 1| ...| ...| ...| ...| ...| 1| ...|
|Anæsthetic (kind not | | | | | | | | |
|stated), | 4| 3| ...| ...| ...| ...| 4| 3|
|Oil of Juniper, | 1| ...| ...| ...| ...| ...| 1| ...|
| | | | | | | | | |
| OPIATES AND NARCOTICS. | | | | | | | | |
| | | | | | | | | |
|Opium, Laudanum--Morphia, | 503| 373| 330| 167| 4 | 2 | 837| 542|
|Soothing Syrup, Paregoric, | | | | | | | | |
|&c. | 18| 22| 2| 3| ...| ...| 20| 25|
|Chlorodyne, | 56| 30| 8| 8| ...| ...| 64| 38|
|Chloral, | 89| 22| 14| 1| 1 | ...| 104| 23|
| | | | | | | | | |
| CYANIDES. | | | | | | | | |
| | | | | | | | | |
|Prussic Acid, and Oil of | | | | | | | | |
| Almonds, | 17| 11| 203| 19| 2 | 8 | 222| 38|
|Potassium Cyanide, | 19| 21| 100| 22| 3 | 1 | 122| 44|
| | | | | | | | | |
| ALKALOIDS. | | | | | | | | |
| | | | | | | | | |
|Strychnine and Nux Vomica, | 22| 21| 65| 85| 4 | 4 | 91| 110|
|Vermin-Killer, | 2| 6| 49| 69| 1 | ...| 52| 75|
|Atropine, | 2| ...| 1| ...| ...| ...| 3| ...|
|Belladonna, | 36| 20| 11| 9| ...| ...| 47| 29|
|Aconite, | 19| 21| 9| 10| ...| ...| 28| 31|
|Ipecacuanha, | 1| 1| ...| ...| ...| ...| 1| 1|
|Cocaine, | 3| ...| ...| ...| ...| ...| 3| ...|
| | | | | | | | | |
| MISCELLANEOUS. | | | | | | | | |
| | | | | | | | | |
|Antipyrine, | 1| ...| ...| ...| ...| ...| 1| ...|
|Cantharides, | 1| ...| ...| 1| ...| ...| 1| 1|
|Camphorated Oil, | 1| ...| ...| ...| ...| ...| 1| ...|
|Croton Oil, | 1| ...| ...| ...| ...| ...| 1| ...|
|Cayenne Pepper, | 1| ...| ...| ...| ...| ...| 1| ...|
|Syrup of Rhubarb, | 1| ...| ...| ...| ...| ...| 1| ...|
|Colchicum, | 2| ...| ...| ...| ...| ...| 2| ...|
|Hemlock, | 3| 1| ...| ...| ...| ...| 3| 1|
|Water Hemlock, | 5| 6| ...| ...| ...| ...| 5| 6|
|Colocynth, | ...| 2| ...| ...| ...| ...| ...| 2|
|Castor Oil Seeds, | 1| 1| ...| ...| ...| ...| 1| 1|
|Laburnum Seeds, | 2| 1| ...| ...| ...| ...| 2| 1|
|Thorn Apple, | 1| ...| ...| ...| ...| ...| 1| ...|
|Yew Leaves or Berries, | 3| 2| ...| ...| ...| ...| 3| 2|
|Crow-foot, | ...| 1| ...| ...| ...| ...| ...| 1|
|Whin-flower, | 1| ...| ...| ...| ...| ...| 1| ...|
|Pennyroyal, | ...| 1| ...| ...| ...| ...| ...| 1|
|Meadow Crow-foot, | ...| 1| ...| ...| ...| ...| ...| 1|
|Arum Seeds, | ...| 1| ...| ...| ...| ...| ...| 1|
|Bitter Aloes, | ...| 1| ...| 1| ...| ...| ...| 2|
|Cocculus Indicus, | ...| ...| 1| ...| ...| ...| 1| ...|
|Horse Chestnut, | ...| 1| ...| ...| ...| ...| ...| 1|
|Creosote, | 1| ...| ...| ...| ...| ...| 1| ...|
|Spirits of Tar (Oil of Tar),| 2| 1| ...| ...| ...| ...| 2| 1|
|Nitro-Glycerine, | 1| ...| ...| ...| ...| ...| 1| ...|
|Camphor, | ...| 1| ...| ...| ...| ...| ...| 1|
|Tobacco, | 4| ...| 1| ...| ...| ...| 5| ...|
|Lobelia, | 1| ...| ...| ...| ...| ...| 1| ...|
|Fungi, | 13| 10| ...| ...| ...| ...| 13| 10|
|Poisonous Weeds, | 2| ...| ...| ...| ...| ...| 2| ...|
|Hellebores, | ...| ...| 1| 1| ...| ...| 1| 1|
|Kind not stated, | 216| 158| 256| 167| 3 | 1 | 475| 326|
| +----+----+----+----+----+----+----+----+
| |2498|1292|1644|1140| 23| 19|4165|2551|
| | \ / | \ / | \ / | \ / |
| | 3790 | 2784 | 42 | 6616 |
+----------------------------+---------+---------+---------+---------+

Although so large a number of substances destroy life by accident or design, yet there are in the list only about 21 which kill about 2 persons or above each year: the 21 substances arranged in the order of their fatality are as follows:--

Actual deaths in
ten years ending 1892.
Caustic potash 19
Poisonous fungi 23
Aconite 59
Mercury 60
Belladonna 76
Sulphuric acid 93
Ammonia 98
Chlorodyne 102
Alcohol 108
Arsenic 110
Chloroform 113
Vermin-killer 127
Chloral 127
Phosphorus 155
Cyanide of potassium 166
Strychnine 201
Nitric acid 204
Prussic acid 260
Carbolic acid 762
Lead 1043
Opiates 1324

In each decade there are changes in the position on the list. The most significant difference between the statistics now given and the statistics for the ten years ending 1880, published in the last edition of this work, is that in the former decade carbolic acid occupied a comparatively insignificant place; whereas in the ten years ending 1892, deaths from carbolic acid poisoning are the most frequent form of fatal poisoning save lead and opiates.

The following table gives some German statistics of poisoning:--

TABLE SHOWING THE ADMISSIONS INTO VARIOUS MEDICAL INSTITUTIONS[30] IN BERLIN OF PERSONS SUFFERING FROM THE EFFECTS OF POISON DURING THE THREE YEARS 1876, 1877, 1878.

[30] Viz., the Königl. Charité, Allg. Städtisches Krankenhaus, Städtisches Baracken-Lazareth, Bethanien, St. Helwög’s-Lazarus, Elisabethen-Krankenhaus, Augusta Hospital, and the Institut für Staatsarzneikunde.

+--------------------------------------+--------+--------+--------+
| | Males. |Females.| Total. |
+--------------------------------------+--------+--------+--------+
| Charcoal Vapour, | 77 | 78 | 155 |
| Sulphuric Acid, | 24 | 54 }| |
| Hydrochloric Acid, | 4 | 4 }| 93 |
| Nitric Acid, and Aqua Regia, | 7 | ... }| |
| Phosphorus, | 13 | 28 | 41 |
| Cyanide of Potassium, | 29 | 3 }| |
| Prussic Acid, | 5 | 1 }| 38 |
| Oxalic Acid, and Oxalate of Potash, | 11 | 8 | 19 |
| Alcohol, | 12 | 2 | 14 |
| Arsenic, | 7 | 5 | 12 |
| Morphine, | 8 | 1 }| |
| Opium, | 2 | 1 }| 12 |
| Potash or Soda Lye, | 2 | 6 | 8 |
| Chloral, | 3 | 4 | 7 |
| Chloroform, | 4 | 2 | 6 |
| Sewer Gas, | 5 | ... | 5 |
| Strychnine, | ... | 4 | 4 |
| Atropine, | 1 | 2 | 3 |
| Copper Sulphate, | 1 | 2 | 3 |
| Nitrobenzol, | 2 | ... | 2 |
| Carbolic Acid, | ... | 2 | 2 |
| Chromic Acid, | 1 | 1 | 2 |
| Burnt Alum, | ... | 1 | 1 |
| Ammonium Sulphide, | 1 | ... | 1 |
| Datura Stramonium, | ... | 1 | 1 |
| Petroleum, | ... | 1 | 1 |
| Benzine, | 1 | ... | 1 |
| Ether, | 1 | ... | 1 |
| Prussic Acid and Morphine, | 1 | ... | 1 |
| Prussic Acid and Chloral, | 1 | ... | 1 |
| Turpentine and Sal Ammoniac, | ... | 1 | 1 |
| +--------+--------+--------+
| | 223 | 212 | 435 |
+--------------------------------------+--------+--------+--------+

=Suicidal Poisoning.=--Poisons which kill more than one person suicidally each year are only 19 in number, as follows:--

Deaths from suicide
during the ten years
ending 1892.

Potassic bichromate 10
Chloroform 14
Chloral 15
Chlorodyne 16
Aconite 19
Belladonna 20
Mercury 24
Nitric acid 27
Ammonia 34
Sulphuric acid 53
Arsenic 77
Phosphorus 84
Vermin-killer 118
Prussic acid 122
Hydrochloric acid 138
Strychnine 150
Oxalic acid 200
Prussic acid 222
Opiates 281
Phenol 290

In the ten years ending 1880, suicidal deaths from vermin-killers, from prussic acid, from cyanide of potassium, and from opiates were all more numerous than deaths from phenol, whereas at present phenol appears to be the poison most likely to be chosen by a suicidal person.

Criminal Poisoning.

§ 22. Some useful statistics of criminal poisoning have been given by Tardieu[31] for the 21 years 1851-1871, which may be summarised as follows:--

[31] _Étude Médico-Légale sur l’Empoisonnement_, Paris, 1875.

Total accusations of Poisoning in the 21 years, 793

RESULTS OF THE POISONING:--
Death, 280 }
Illness, 346 } 872
Negative, 246 }

ACCUSED:--
Men, 304 } 703
Women, 399 }

NATURE OF POISON EMPLOYED:--
Arsenic, 287
Phosphorus, 267

{ Sulphate, 120 }
Copper { Acetate (Verdigris), 39 } 159

{ Sulphuric Acid, 36 }
Acids { Hydrochloric Acid, 8 } 47
{ Nitric Acid, 3 }

Cantharides, 30

Nux Vomica, 5 } 12
Strychnine, 7 }

{ Opium, 6 }
Opiates { Laudanum, 3 } 10
{ Sedative Water, 1 }

Salts of Mercury, 8

Sulphate of Iron, 6

Preparations of Antimony, 5

Ammonia, 4

Cyanides {Prussic Acid, 2 }
{Cyanide of Potassium, 2 } 4

Hellebore, 3

Datura Stramonium, 3

Powdered Glass, 3

Digitalin, 2

Potash, 2

Sulphate of Zinc, 2

Eau de Javelle (a solution of Hypochlorite of Potash), 1

Tincture of Iodine, 1

Croton Oil, 1

Nicotine, 1

Belladonna, 1

“Baume Fiovarenti,” 1

Euphorbia, 1

Acetate of Lead, 1

Carbonic Acid Gas, 1

Laburnum Seeds, 1

Colchicum, 1

Mushrooms, 1

Sulphuric Ether, 1
---
Total, 867
===

It hence may be concluded, according to these statistics of criminal poisoning, that of 1000 attempts in France, either to injure or to destroy human life by poison, the following is the most probable selective order:--

Arsenic, 331
Phosphorus, 301
Preparations of Copper, 183
The Mineral Acids, 54
Cantharides, 35
Strychnine, 14
Opiates, 12
Mercurial preparations, 9
Antimonial preparations, 6
Cyanides (that is, Prussic Acid and Potassic Cyanide), 5
Preparations of Iron, 5

This list accounts for 955 poisonings, and the remaining 45 will be distributed among the less used drugs and chemicals.

IV.--The Connection between Toxic Action and Chemical Composition.

§ 23. Considerable advance has been made of late years in the study of the connection which exists between the chemical structure of the molecule of organic substances and physiological effect. The results obtained, though important, are as yet too fragmentary to justify any great generalisation; the problem is a complicated one, and as Lauder Brunton justly observes:--

“The physiological action of a drug does not depend entirely on its chemical composition nor yet on its chemical structure, so far as that can be indicated even by graphic formula, but upon conditions of solubility, instability, and molecular relations, which we may hope to discover in the future, but with which we are as yet imperfectly acquainted.”[32]

[32] _Introduction to Modern Therapeutics_, Lond., 1892. 136.

The occurrence of hydroxyl, whether the substance belong to the simpler chain carbon series or to the aromatic carbon compounds, appears to usually endow the substance with more or less active and frequently poisonous properties, as, for example, in the alcohols, and as in hydroxylamine. It is also found that among the aromatic bodies the toxic action is likely to increase with the number of hydroxyls: thus phenol has one hydroxyl, resorcin two, and phloroglucin three; and the toxic power is strictly in the same order, for, of the three, phenol is least and phloroglucin most poisonous.

Replacing hydrogen by a halogen, especially by chlorine, in the fatty acids mostly produces substances of narcotic properties, as, for instance, monochloracetic acid. In the sulphur compounds, the entrance of chlorine modifies the physiological action and intensifies toxicity: thus ethyl sulphide (C₂H₅)₂S is a weak poison, monochlorethyl sulphide C₂H₅C₂H₄ClS a strong poison, and dichlorethyl sulphide C₄H₈Cl₂S a very strong poison: the vapour kills rabbits within a short time, and a trace of the oil applied to the ear produces intense inflammation of both the eyes and the ear.[33]

[33] V. Meyer, _Ber. d. Chem. Ges._, XX., 1725.

The weight of the molecule has an influence in the alcohols and acids of the fatty series; for instance, ethyl, propyl, butyl, and amyl alcohols show as they increase in carbon a regular increase in toxic power; the narcotic actions of sodium propionate, butyrate, and valerianate also increase with the rising carbon. Nitrogen in the triad condition in the amines is far less poisonous than in the pentad condition.

Bamberger[34] distinguishes two classes of hydrogenised bases derived from α and β naphthylamine, by the terms “acylic” and “aromatic.” The acylic contains the four added hydrogens in the amidogen nucleus, the aromatic in the other nucleus, thus

[34] _Ber._, xxii. 777-778.

CH CNH₂
/\ /\
/ \C/ \
CH | | | CH
| | |
CH | | | CH
\ /C\ /
\/ \/
CH CH

α Naphthylamine.

CH CH
/\ /\
/ \C/ \
CH | | | CNH₂
| | |
CH | | | CH
\ /C\ /
\/ \/
CH CH

β Naphthylamine.

CH CH₂
/\ /\
/ \C/ \
CH | | | CNH₃
| | |
CH | | | CH₂
\ /C\ /
\/ \/
CH CH₂

Acylic tetrahydro-α Naphthylamine.

CH₂ CH
/\ /\
/ \C/ \
CH₂ | | | CNH₂
| | |
CH₂ | | | CH
\ /C\ /
\/ \/
CH₂ CH

Aromatic tetrahydro-β Naphthylamine.

The acylic β tetrahydro-naphthylamine, the β tetrahydroethylnaphthylamine, and the β tetrahydromethylnaphthylamine all cause dilatation of the pupil and produce symptoms of excitation of the cervical sympathetic nerve; the other members of the group are inactive.

§ 24. The result of replacing hydrogen by alkyls in aromatic bodies has been studied by Schmiedeberg and others; replacing the hydrogen of the amidogen by ethyl or methyl, usually results in a body having a more or less pronounced narcotic action. The rule is that methyl is stronger than ethyl, but it does not always hold good; ortho-amido-phenol is not in itself poisonous, but when two hydrogens of the amidogen group are replaced by two methyls thus--

HO
/\
/ \
| |NH₂
| |
| |
\ /
\/

HO
/\
/ \
| |N(CH₃)₂
| |
| |
\ /
\/

the resulting body has a weak narcotic action.

It would naturally be inferred that the replacement of the H in the hydroxyl by a third methyl would increase this narcotic action, but this is not so: on the other hand, if there are three ethyl groups in the same situation a decidedly narcotic body is produced.

The influence of position of an alkyl in the aromatic bodies is well shown in ortho-, para- and meta-derivatives. Thus the author proved some years ago that with regard to disinfecting properties, ortho-cresol was more powerful than meta-; meta-cresol more powerful than para-; so again ortho-aceto-toluid is poisonous, causing acute nephritis; meta-aceto-toluid has but feeble toxic actions but is useful as an antipyretic; and para-aceto-toluid is inactive.

In the trioxybenzenes, in which there are three hydroxyls, the toxic action is greater when the hydroxyls are consecutive, as in pyrogallol, than when they are symmetrical, as in phloroglucin.

OH
/\
/ \
| |OH
| |
| |OH
\ /
\/

Pyrogallol.

OH
/\
/ \
| |
| |
HO| |OH
\ /
\/

Phloroglucin.

The introduction of methyl into the complicated molecule of an alkaloid often gives curious results: thus methyl strychnine and methyl brucine instead of producing tetanus have an action on voluntary muscle like curare.

Benzoyl-ecgonine has no local anæsthetic action, but the introduction of methyl into the molecule endows it with a power of deadening the sensation of the skin locally; on the other hand, cocethyl produces no effect of this kind.

Drs. Crum Brown and Fraser[35] have suggested that there is some relation between toxicity and the saturated or non-saturated condition of the molecule.

[35] _Journ. Anat. and Phys._, vol. ii. 224.

Hinsberg and Treupel have studied the physiological effect of substituting various alkyls for the hydrogen of the hydroxyl group in para-acetamido-phenol.

Para-aceto-amido-phenol when given to dogs in doses of 0.5 grm. for every kilogr. of body weight causes slight narcotic symptoms, with slight paralysis; there is cyanosis and in the blood much methæmoglobin.

In men doses of half a gramme (7·7 grains) act as an antipyretic, relieve neuralgia and have weak narcotic effects.

The following is the result of substituting certain alkyls for H in the HO group.

(1) =Methyl.=--The narcotic action is strengthened and the antipyretic action unaffected. The methæmoglobin in the blood is somewhat less.

(2) =Ethyl.=--Action very similar, but much less methæmoglobin is produced.

(3) =Propyl.=--Antipyretic action a little weaker. Methæmoglobin in the blood smaller than in para-acetamido-phenol, but more than when the methyl or ethyl compound is administered.

(4) =Amyl.=--Antipyretic action decreased.

The smallest amount of toxicity is in the ethyl substitution; while the maximum antipyretic and antineuralgic action belongs to the methyl substitution.

Next substitution was tried in the Imid group. It was found that substituting ethyl for H in the imid group annihilated the narcotic and antipyretic properties. No methæmoglobin could be recognised in the blood.

Lastly, simultaneous substitution of the H of the HO group by ethyl and the substitution of an alkyl for the H in the NH group gave the following results:--

=Methyl.=--In dogs the narcotic action was strengthened, the methæmoglobin in the blood diminished. In men the narcotic action was also more marked as well as the anti-neural action. The stomach and kidneys were also stimulated.

=Ethyl.=--In dogs the narcotic action was much strengthened, while the methæmoglobin was diminished. In men the antipyretic and anti-neural actions were unaffected.

=Propyl.=--In dogs the narcotic action was feebler than with methyl or ethyl, and in men there was diminished antipyretic action.

=Amyl.=--In dogs the narcotic action was much smaller.

From this latter series the conclusion is drawn that the maximum of narcotic action is obtained by the introduction of methyl and the maximum antipyretic action by the introduction of methyl or ethyl. The ethyl substitution is, as before, the less toxic.[36]

[36] _Ueber die physiologische Wirkung des p-amido-phenol u. einiger Derivate desselben._ O. Hinsberg u. G. Treupel, _Archiv f. Exp. Pathol. u. Pharm._, B. 33, S. 216.

The effect of the entrance of an alkyl into the molecule of a substance is not constant; sometimes the action of the poison is weakened, sometimes strengthened. Thus, according to Stolnikow, dimethyl resorcin, C₆H₄(OCH₃)₂, is more poisonous than resorcin C₆H₄(OH)₂. Anisol C₆H₅OCH₃, according to Loew, is more poisonous to algæ, bacteria, and infusoria than phenol C₆H₅OH. On the other hand, the replacement by methyl of an atom of hydrogen in the aromatic oxyacids weakens their action; methyl salicylic acid

O.CH₃
/
C₆H₄
\
COOH

is weaker than salicylic acid

OH
/
C₆H₄ .
\
COOH

Arsen-methyl chloride, As(CH₃)Cl₂, is strongly poisonous, but the introduction of a second methyl As(CH₃)₂Cl makes a comparatively weak poison.

§ 25. In some cases the increase of CO groups weakens the action of a poison; thus, in allantoin there are three carbonyl (CO) groups; this substance does not produce excitation of the spinal cord, but it heightens muscular irritability and causes, like xanthin, muscular rigidity; alloxantin, with a similar structure but containing six carbonyl groups, does not possess this action.

NH--CH--NH
| | |
CO | CO
| | |
NH--CO NH₂

Allantoin.

Alloxantin.

§ 26. A theory of general application has been put forward and supported with great ability by Oscar Loew[37] which explains the action of poisons by presuming that living has a different composition to dead albumin; the albumin of the chemist is a dead body of a definite composition and has a stable character; living albumin, such as circulates in the blood or forms the protoplasm of the tissues, is not “stable” but “labile”; Loew says:--“If the old idea is accepted that living albumin is chemically the same substance as that which is dead, numerous toxic phenomena are inexplicable. It is impossible, for instance, to explain how it is that diamide N₂H₄ and hydroxylamine NH₂OH are toxic, even with great dilution, on all living animals; whilst neither of those substances have the smallest action on dead plasma or the ordinary dissolved passive albumin, there must therefore be present in the albumin of the living plasma a grouping of atoms in a “_labile_” condition (_Atomgruppirungen labiler Art_) which are capable of entering into reactions; such, according to our present knowledge, can only be the aldehyde and the ketone groups. The first mentioned groups are more labile and react in far greater dilution than the latter groups.”

[37] _Ein natürliches System der Gift-Wirkungen_, München, 1893.

Loew considers that all substances which enter into combination with aldehyde or ketone groups must be poisonous to life generally. For instance, hydroxylamine, diamide and its derivatives, phenylhydrazine, free ammonia, phenol, prussic acid, hydric sulphide, sulphur dioxide and the acid sulphites all enter into combination with aldehyde.

So again the formation of imide groups in the aromatic ring increases any poisonous properties the original substance possesses, because the imide group easily enters into combination with aldehyde; thus piperidine (CH₂)₅NH is more poisonous than pyridine (CH)₅N; coniine NH(CH₂)₄CH-CH₂-CH₂CH₃, is more poisonous than collidine N(CH)₄C-CH-(CH₃)₂; pyrrol (CH)₄NH than pyridine (CH)₅N; and amarin,[38]

C₆H₅-CH-NH
| \
| CH-C₆H₅,
| /
C₆H₅-C=N

than hydrobenzamide

C₆H₅-CH=N
\
CH-C₆H₅.
/
C₆H₅-CH=N

[38] Th. Weyl (_Lehrbuch der organischen Chemie_) states (p. 385) that amarin is not poisonous, but Baccheti (_Jahr. d. Chemie_, 1855) has shown that 250 mgrms. of the acetate will kill a dog, 80 mgrms. a guinea-pig; and that it is poisonous to fishes, birds, and frogs: hydrobenzamide in the same doses has no effect.

If the theory is true, then substances with “labile” amido groups, on the one hand, must increase in toxic activity if a second amido group is introduced; and, on the other, their toxic qualities must be diminished if the amido group is changed into an imido group by the substitution of an atom of hydrogen for an alkyl.

Observation has shown that both of these requirements are satisfied; phenylenediamine is more poisonous than aniline; toluylenediamine more poisonous than toluidine. Again, if an atom of hydrogen in the amido (NH₂) group in aniline be replaced by an alkyl, _e.g._ methyl or ethyl, the resulting substance does not produce muscular spasm; but if the same alkyl is substituted for an atom of hydrogen in the benzene nucleus the convulsive action remains unaffected.

If an acidyl, as for example the radical of acetic acid, enter into the amido group, then the toxic action is notably weakened; thus, acetanilide is weaker than aniline, and acetylphenylhydrazine is weaker than phenylhydrazine. If the hydrogen of the imido group be replaced by an alkyl or an acid radical, and therefore tertiary bound nitrogen restored, the poisonous action is also weakened.

In xanthin there are three imido groups; the hydrogen of two of these groups is replaced by methyl in theobromin; and in caffein the three hydrogens of the three imido groups are replaced by three methyls, thus:--

Xanthin.

Theobromin.

Caffein.

and experiment has shown that theobromin is weaker than xanthin, and caffein still weaker than theobromin.

Loew[39] makes the following generalisations:--

[39] _Ein natürliches System der Gift-Wirkungen_, München, 1893.

1. Entrance of the carboxyl or sulpho groups weakens toxic action.

2. Entrance of a chlorine atom exalts the toxic character of the catalytic poisons (Loew’s catalytic poisons are alcohols, ether, chloroform, chloral, carbon tetrachloride, methylal, carbon disulphide and volatile hydrocarbons).

3. Entrance of hydroxyl groups in the catalytic poisons of the fatty series weakens toxic character; on the other hand, it exalts the toxicity of the substituting poisons. (Examples of Loew’s class of “substituting” poisons are hydroxylamine, phenylhydrazine, hydric cyanide, hydric sulphide, aldehyde, and the phenols.)

4. A substance increases in poisonous character through every influence which increases its power of reaction with aldehyde or amido groups. If, for example, an amido or imido group in the poison molecule be made more “labile,” or if thrice linked nitrogen is converted into nitrogen connected by two bands, whether through addition of water or transposition (_umlagerung_) or if a second amido group enters, the poisonous quality is increased. Presence of a negative group may modify the action.

5. Entrance of a nitro group strengthens the poisonous character. If a carboxyl or a sulpho group is present in the molecule, or if, in passing through the animal body, negative groups combine with the poison molecule, or carboxyl groups are formed in the said molecule; in such cases the poisonous character of the nitro group may not be apparent.

6. Substances with double carbon linkings are more poisonous than the corresponding saturated substances. Thus neurine with the double linking of the carbon of CH₂ is more poisonous than choline; vinylamine than ethylamine.

CH==CH₂
/
(CH₃)₃N
\
OH

Neurine.

CH₂--CH₂OH
/
(CH₃)₃N
\
OH

Choline.

CH₂
║
CH.NH₂

Vinylamine.

CH₃
|
CH₂.NH₂

Ethylamine.

§ 27. M. Ch. Michet[40] has investigated the comparative toxicity of the metals by experiments on fish, using species of _Serranus_, _Crenolabrus_, and _Julius_. The chloride of the metal was dissolved in water and diluted until just that strength was attained in which the fish would live 48 hours; this, when expressed in grammes per litre, he called “_the limit of toxicity_.”

[40] “_De la Toxicité comparée des différents Métaux._” _Note de M. Ch. Michet. Compt. Rend._, t. xciii., 1881, p. 649.

The following is the main result of the inquiry, by which it will be seen that there was found no relation between “the limit of toxicity” and the atomic weight.

TABLE SHOWING THE RESULTS OF EXPERIMENTS ON FISH.

No. of Limit of
Experiments. Metal. Toxicity.

20. Mercury, ·00029
7. Copper, ·0033
20. Zinc, ·0084
10. Iron, ·014
7. Cadmium, ·017
6. Ammonium, ·064
7. Potassium, ·10
10. Nickel, ·126
9. Cobalt, ·126
11. Lithium, ·3
20. Manganese ·30
6. Barium, ·78
4. Magnesium, 1·5
20. Strontium, 2·2
5. Calcium, 2·4
6. Sodium, 24·17

V.--Life-Tests; or the Identification of Poison by Experiments on Animals.

§ 28. A philosophical investigation of poisons demands a complete methodical examination into their action on every life form, from the lowest to the highest. Our knowledge is more definite with regard to the action of poisons on man, dogs, cats, rabbits, and frogs than on any other species. It may be convenient here to make a few general remarks as to the action of poisons on infusoria, the cephalopoda, and insects.

=Infusoria.=--The infusoria are extremely sensitive to the poisonous alkaloids and other chemical agents. Strong doses of the alkaloids cause a contraction of the cell contents, and somewhat rapid disintegration of the whole body; moderate doses at first quicken the movements, then the body gets perceptibly larger, and finally, as in the first case, there is disintegration of the animal substance.

Rossbach[41] gives the following intimations of the proportion of the toxic principle necessary to cause death:--Strychnine 1 part dissolved in 1500 of water; veratrine 1 in 8000; quinine 1 in 5000; atropine 1 in 1000; the mineral acids 1 in 400-600; salts 1 in 200-300.

[41] N. J. Rossbach, _Pharm. Zeitschr. für Russland_, xix. 628.

The extraordinary sensitiveness of the infusoria, and the small amount of material used in such experiments, would be practically useful if there were any decided difference in the symptoms produced by different poisons. But no one could be at all certain of even the class to which the poison belongs were he to watch, without a previous knowledge of what had been added to the water, the motions of poisoned infusoria. Hence the fact is more curious than useful.

=Cephalopoda.=--The action of a few poisons on the cephalopoda has been investigated by M. E. Yung.[42] Curara placed on the skin had no effect, but on the branchiæ led to general paralysis. If given in even fifteen times a greater dose than necessary to kill a rabbit, it was not always fatal. Strychnine, dissolved in sea-water, in the proportion of 1 to 30,000, causes most marked symptoms. The first sign is relaxation of the chromataphore muscle and the closing of the chromataphores; the animal pales, the respiratory movements become more powerful, and at the end of a notable augmentation in their number, they fall rapidly from the normal number of 25 to 5 a minute. Then tetanus commences after a time, varying with the dose of the poison; the arm stiffens and extends in fan-like form, the entire body is convulsed, the respiration is in jerks, the animal empties his pouch, and at the end of a few minutes is dead, in a state of great muscular rigidity. If at this moment it is opened, the venous heart is found still beating. Nicotine and other poisons were experimented with, and the cephalopoda were found to be generally sensitive to the active alkaloids, and to exhibit more or less marked symptoms.

[42] _Compt. Rend._, t. xci. p. 306.

=Insects.=--The author devoted considerable time, in the autumn of 1882, to observations on the effect of certain alkaloids on the common blow-fly, thinking it possible that the insect would exhibit a sufficient series of symptoms of physiological phenomena to enable it to be used by the toxicologist as a living reagent. If so, the cheapness and ubiquity of the tiny life during a considerable portion of the year would recommend it for the purpose. Provided two blow-flies are caught and placed beneath glass shades--the one poisoned, the other not--it is surprising what a variety of symptoms can, with a little practice, be distinguished. Nevertheless, the absence of pupils, and the want of respiratory and cardiac movements, are, in an experimental point of view, defects for which no amount or variety of merely muscular symptoms can compensate.

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Poisons, Their Effects and DetectionChapter XIV: Part II: I.--Definition of Poison (1)

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