An Accumulative Poison. Many doses are required; the effects being produced by the repetition of doses which would, individually, be harmless.
There still remains another point of view in which it is essential to regard the operation of a poison, in order to establish a distinction between those substances which, in a given dose, will destroy life under every circumstance of constitution, and those which occasion death in consequence of some constitutional peculiarity in the individual to whom they may have been administered, and which are innocuous to the general mass of mankind; the gradations by which food, medicine, and poison, are thus enabled to branch into each other cannot be defined, because the circumstances with which they are related, defy generalization. The distinction, however, must be acknowledged and preserved, and we know no terms better adapted for expressing it than those of Absolute and Relative poisons; and our readers are accordingly requested to receive them in conformity with this explanation, whenever they occur in the following pages. Every work professing to treat the subject of Poisons, abounds with instances, in which articles that, by universal consent, are considered innocuous, have occasioned the most direful effects. Morgagni relates a case of a person who died from eating bread made with the farina of the chesnut. Dr. Winterbottom[[151]] says that he is subject to severe nettle-rash after eating sweet almonds. Schenkius relates a case in which the general law of astringents and cathartics was always reversed. Donatus tells us of a boy whose jaws swelled, whose face broke out in spots, and whose lips frothed, whenever he eat an egg: we might add many more examples, but it is needless to encumber a subject with illustrations which is already so obvious and indisputable. Nor do the anomalies of constitutional idiosyncrasies end here, for they not only convert food into poison, but they change poison into food, or at least, into a harmless repast. The most extraordinary exemplification of this on record is contained in the history of the old man at Constantinople, as related by M. Pouqueville, physician to the French army in Egypt, and who was a prisoner at Constantinople in the year 1798[[152]]. “This man,” says he, “was well known all over Constantinople, by the name of Suleyman Yeyen, or Suleyman, the taker of corrosive sublimate. At the epoch when I was there he was supposed to be nearly a hundred years old, having lived under the Sultans Achmet III, Abdul Hamet, and Selim III. He had in early life habituated himself to taking opium; but, notwithstanding that he constantly increased the dose, he ceased to feel from it the desired effect, and then tried sublimate, the effects of which he had heard highly spoken of; for thirty years this old man never ceased to take it daily, and the quantity he could now bear exceeded a drachm. It is said, at this epoch he came into the shop of a Jewish apothecary, and asked for a drachm of sublimate, which he swallowed immediately, having first mixed it in a glass of water. The apothecary, terrified, and fearing that he should be accused of poisoning a Turk, immediately shut up his shop, reproaching himself bitterly with what he had done; but his surprise was very great, when, the next day, the Turk came again, and asked for a like dose of sublimate.”
Morbid states of the body may also exist which are capable of resisting, to a certain extent, or of modifying, the violent operation of particular poisons. In the history of the Royal Academy of Sciences for 1703, a case is related of a woman, who being tired out by a protracted dropsy, under which her husband had suffered, charitably administered to him fifteen or twenty grains of opium with the intention of despatching him; but the dose immediately produced such copious evacuations by sweat and urine, that it restored him to health. This relation will immediately recal to the recollection of the classical reader the story, recorded by Plutarch, in his life of Crassus, of Hyrodes king of the Parthians, who having fallen into a dropsical complaint had poison (Aconite) administered to him by his second son, Phraates, but which, instead of destroying the king, as intended, cured his disease. The son, however, having thus failed in his attempt, shortly afterwards smothered his father with his pillow.
GENERAL REMARKS
ON THE MEDICAL EVIDENCE REQUIRED TO SUBSTANTIATE AN ACCUSATION OF POISONING.
Although the phenomena by which we are enabled to discover the administration of poison, will be fully enumerated, and carefully examined, under the history of each particular substance, and will necessarily vary according to the chemical properties, and physiological action of each individual poison; yet there are some general points of evidence, and several questions of importance, upon which it is very essential to arrive at some definite conclusion, some fixed understanding, before we proceed to the consideration of the particular details, and subordinate ramifications, of this complicated subject.
The great constituents which form the medical proof of poisoning, are derived from Chemical, Anatomical, and Pathological researches; viz.—the existence of poison in the stomach or intestines; the morbid appearances, corresponding to such poison, upon dissection; and the characteristic symptoms which accompanied the action of it, previous to death. Where these circumstances occur in combination, the demonstration may be said to be complete, for we have arrived at absolute certainty.
But scientific evidence, short of such perfection, may be amply sufficient to lead to conviction. The fact of a poison having been found in the body may supersede the necessity of pathological testimony: thus Hoffman,[[153]] “Si venenum adhuc intra ventriculum reperitur, res est clarissima, ubi vero, illud haud deprehenditur, res adhuc dubii plena est.” We shall hereafter find that the discovery of organic lesions, without the chemical proof (“experimentum crucis[[154]]”) is often vague, and seldom satisfactory, and that even when sanctioned by the testimony of the pathologist, will frequently be deemed insufficient to sustain an indictment, unless indeed it be collaterally supported by a very strong chain of circumstantial evidence of a moral nature, especially such as relates to the character, conduct, and presumed object of the prisoner.
As the duty of the medical witness, upon such occasions, must always be anxious, and generally perplexing, it becomes our duty at least to clear away those adventitious difficulties with which ignorance on the one hand, and sophistry on the other, have obstructed a path of inquiry, which, from its very nature and direction, must necessarily be obscure and intricate.
We shall endeavour upon this, as we have upon similar occasions, to bring the more leading and popular points of controversy within the scope of a few prominent questions, assigning to each a share of attention, commensurate with our idea of its importance.
Q. 1. Whether all, or most of the symptoms, characteristic of the action of corrosive and narcotic poisons, may not arise from morbid causes of spontaneous origin?