Читать книгу Treatise on Poisons - Robert Sir Christison - Страница 13

It is not my object to treat under this head of the moral evidence generally, which is required to establish a charge of poisoning. But as it is well known that in criminal trials medical witnesses have for the most part nothing to do with the moral proof, while at the same time in cases of poisoning the medical and moral circumstances are always intimately interwoven and apt to be confounded together, it is necessary for me to specify those particulars of the moral evidence, which either require some medical skill to appreciate them, or fall naturally under the cognizance of the physician in his quality of practitioner. I shall enter into greater details under this section than may perhaps appear to the medical reader necessary, chiefly that I may redeem the pledge given in the introduction to the lawyer and general reader, and endeavour to show how powerful an instrument a medico-legal investigation may become in skilful hands, for throwing light on almost every branch of the evidence.

The moral or general proof in charges of poisoning is almost always circumstantial only. The circumstances of which it usually consists relate, 1. To suspicious conduct on the part of the prisoner before the event, such as dabbling with poisons when he has nothing to do with them in the way of his profession, or conversing about them, or otherwise showing a knowledge of their properties not usual in his sphere of life:—2. To the purchase or possession of poison recently before the date of the alleged crime, and the procuring it in a secret manner, or under false pretences, such as for poisoning rats when there are none on his premises, or for purposes to which it is never applied:—3. To the administration of poison either in food, drink, medicine, or otherwise:—4. To the intent of the prisoner, such as the impossibility of his having administered the poison ignorantly, or by accident, or for beneficial purposes, alleged or not alleged:—5. To the fact of other members of the family besides the deceased having been similarly and simultaneously affected:—6. To suspicious conduct on the part of the prisoner during the illness of the person poisoned,—such as directly or indirectly preventing medical advice being obtained, or the relations of the dying man being sent for, or showing an over-anxiety not to leave him alone with any other person, or attempting to remove or destroy articles of food or drink, or vomiting matter which may have contained the poison, or expressing a foreknowledge of the probability of speedy death:—7. To suspicious conduct after the person’s death, such as hastening the funeral, preventing or impeding the inspection of the body, giving a false account of the previous illness, showing an acquaintance with the real or supposed effects of poison on the dead body:—8. To the personal circumstances and state of mind of the deceased, his death-bed declaration, and other particulars, especially such as tend to prove the impossibility or improbability of suicide:—9. To the existence of a motive or inducement on the part of the prisoner, such as his having a personal quarrel with the deceased, or a hatred of him,—his succeeding to property by his death, or being relieved of a burthen by it,—his knowing that the deceased was with child by him.

Upon many of the particulars now enumerated, important evidence may be derived from the medical part of the investigation; and not unfrequently such evidence can be collected or appreciated only by means of a medico-legal inquiry.

1 and 2. On the first two articles, suspicious conduct or conversation on the part of the prisoner before the crime, and the possession or purchase of poison by him, little or nothing need be said. The medical witness may of course be asked whether the conduct or conversation proved betokens an unusual acquaintance with poisons and their effects. And his opinion may be referred to regarding the nature of suspected articles found in the prisoner’s possession. As to the purchase of arsenic under the false pretence of poisoning rats, it may be observed, that a great deal more stress is usually laid on such evidence than it seems to deserve; for there are few houses, in the country particularly, which are not more or less infected by them. On the other hand, too little weight is attached to the circumstance of the purchaser not having warned his household of poison being laid. Such conduct ought in my opinion to be accounted extremely suspicious; for so far as I have remarked, the fear with which unprofessional persons regard the common poisons is such, that I can hardly believe any master of a house would actually lay poison without warning the servants and other inmates of his having done so.

3. The next article, which relates to the proof of the administration of poison, will require some details.

Direct proof of the administration of poison by the actual giver is very rarely attainable, that part of the transaction being for the most part easily concealed. The proof of this point is justly accounted, however, a very important part of the evidence; nay, on some recent trials in this country the prosecution has failed apparently for want of such evidence, although the case was complete in every other particular. It is generally constituted by a chain of circumstances, and these are often strictly medical, as will now be shown by a few examples.

In the first place, pointed evidence as to the individual who gave the poison may be derived from the chemical investigation,—for example, from the comparative results of the analysis of the poisoned dish, and of the articles of which it consisted. I am indebted to my colleague, Dr. Alison, for the following excellent illustration from the case of William Muir, who was condemned at Glasgow in 1812 for poisoning his wife. In the course of the day on which she took ill she was visited by a farmer of the neighbourhood, who had studied physic a little in his youth. He learned from her that she had breakfasted on porridge a short time before she felt herself ill, and that she suspected the porridge to have been poisoned. He immediately procured the wooden bowl or cap in which the cottagers of Scotland keep the portion of meal used each time for making the porridge; and finding in it some meal, with shining particles interspersed, he wrapped a sample in paper, and took the proper measures for preserving its identity. He then secured also a sample from the family store in a barrel. The two particles were produced by him on the trial; and from experiments made in court the late Dr. Cleghorn was enabled to declare, that the meal from the bowl contained arsenic, and that the meal from the barrel did not. These facts, besides proving that the woman had next to a certainty taken arsenic in the porridge, likewise, in conjunction with other slight moral circumstances, established that the poison had been mixed with the meal in the house, and on the morning when the deceased took ill, before any stranger entered the house. The procedure of this farmer was precisely that which ought to be followed by the medical practitioner in a similar conjuncture.

An instance of an opposite description related by M. Barruel also deserves notice, as showing how evidence of this kind may afford, in otherwise suspicious circumstances, a strong presumption of accidental poisoning. Sixteen people near Bressières in France having been severely affected with vomiting and colic immediately after dinner, the bread, which was suspected, was examined by Barruel, and found to contain a little arsenic. The flour of which the bread was made had been taken from a large store of it, which, on being examined, was also found to be similarly impregnated. As it was extremely improbable that any one either could or would poison so large a mass of flour, to attain any malicious object, it was inferred that the arsenic had been mixed with it accidentally, and that the accident might have arisen from grain having been taken by mistake to the flour-mill to be ground, which had been intended originally for seed, and sprinkled with arsenic to destroy insects.^[121]

It may be worth while observing, in the present place, that in the instance of poisoned wine very important evidence may be obtained by examining whether the wine with which the cork is impregnated contains any traces of the poison. This method of investigation occurred to me in a very singular case of poisoning with arsenic in champagne, which happened in a baronet’s family in Scotland. In this instance, however, such analysis was proved to be unnecessary; for the gentleman himself brought the bottle from his cellar, broke the wires and drew the cork, immediately before the wine was drunk.^[122]

All evidence of the like nature, though it is at present often procured from other sources, should, for obvious reasons, be invariably collected, if possible, with the aid of a medical person. If again a medical man is called to a patient evidently affected with suspicious symptoms, and finds himself obliged to declare such to be his opinion, his thoughts, as soon as he has given directions for the treatment, should be turned towards that part of the evidence, for the securing of which he is naturally looked to as the person best qualified by previous education and his opportunities at the moment. With this view, therefore, having ascertained in what articles it is possible for poison to have been administered, he should at once endeavour to secure the remains of the particular portion partaken of by his patient, as well of the general dish, if it is an article of food, and of the ingredients of which the dish was ostensibly made, not forgetting the salt with which it was seasoned. A case occurred some years ago in the north of Scotland, in which arsenic was administered in porridge by mixing it with the salt.

It is of great consequence, before proceeding to analyze such articles, for example suspected dishes,—to be particular in investigating every thing connected with the cooking, serving, and eating of them. By doing so, not only will the chemical analysis be facilitated, but likewise facts in it will be accounted for, which might otherwise prove embarrassing, and even lead to the drawing of false conclusions from the result of the analysis. This statement is very well exemplified by the following incident which occurred to myself. In 1827 a family in Portobello were poisoned by the maid-servant; and it was believed, that, for the sake of a trick, she had, while carrying to the oven the beef subsequently used at dinner, maliciously mixed with it tartar-emetic or some other poison. One-half of the beef having been preserved, and two persons of the family having been very severely affected, Dr. Turner and I, to whom the case was remitted, made little doubt that we should discover the poison by chemical analysis: but we did not. Being subsequently employed by the sheriff to inquire into the particulars, I found that the poison had been mixed with the gravy, which had been consumed almost to the last drop,—that the gravy had been poured over the beef,—that the upper half of the beef had been eaten,—and that the remainder which we analysed had been transferred upon a different plate from that on which it was served for dinner. These particulars accounted sufficiently for the poison not having been discovered.

Another mode in which the chemical part of the inquiry may contribute to discover the individual who administered the poison is by a comparative examination of the persons of the deceased and the accused. The following very pointed illustration has been published by MM. Ollivier and Chevallier of Paris.—A woman who lived on bad terms with her husband was found dead on a roadside the morning after having been seen drunk in his company in the neighbourhood. The mouth, throat, and gullet were proved by a careful analysis to be corroded with nitric acid, the stains and traces of which were also found on various parts of her dress, and on the hair, neck, and arms, but not on her hands, and not lower down the alimentary canal than the upper fourth of the gullet. Ollivier, suspecting from these appearances, that she had not taken the acid voluntarily, requested to see the husband; whereupon there were found on his coat, trousers, and hands, a great number of stains, which, like those on the deceased, were proved by chemical analysis to have been produced by nitric acid. Here it was scarcely possible to avoid inferring, that the man got these stains while endeavouring to force his intoxicated wife to take the poison Marks of nail scratches were also observed round the mouth and on the throat; whence it was reasonably inferred, that, having failed in his original plan, he had suffocated her with his hands.^[123]

While these illustrations are given of the conclusiveness of the chemical evidence in fixing the administration of poison on a particular individual, it is essential likewise to observe that the same kind of evidence may be at times equally conclusive of the innocence of a person unjustly suspected. This obvious and important application of a chemical inquiry is forcibly suggested by the following particulars of an incident related by M. Chevallier:—An individual was accused by a woman of having tried to poison her; and she represented that he had put the poison into her soup, while it stood from one day to another in an iron pot. On making a careful analysis of some of the soup which remained, Chevallier found it so strongly impregnated with copper, that, supposing the sulphate was the salt mixed with the soup, ten ounces must have contained twenty-two grains. It then occurred to him, that it was important to examine the iron pot, in which the poisoned soup was represented to have been kept; for the probability was that a large quantity of the copper, if any salt of that metal had really been contained in the soup, would have been thrown down by the superior affinity of the iron, and consequently that a coppery lining would be found on the inside. He was led, however, to anticipate that no copper would be found there, because there was no iron dissolved in the soup, as would have been the case if copper had been precipitated from it by the iron of the pot. And accordingly he not only found no copper lining the inside of the pot; but likewise, on following the process described by the accuser as the one pursued in cooking the soup and in subsequently poisoning it, he satisfied himself by express trial that there was nothing in the circumstances of the case which could have prevented the iron from exerting its usual action on the salts of copper. These conclusions, coupled with certain facts of general evidence, proved substantially that the suspected person had nothing to do with the crime charged against him; and he was therefore discharged.^[124] A case somewhat similar will be related under the head of Imputed Poisoning.

In the second place, evidence as to the person who administered the poison may be procured by considering the commencement of the symptoms, in relation to the time at which particular articles have been given in a suspicious manner by a particular individual. The import of facts of this nature can be properly appreciated only by the medical witness; for he alone can be acknowledged as conversant with the symptoms which poisons produce, the intervals within which they begin to operate, and the circumstances in which their operation may be put off or accelerated.

Few cases will occur in which it is not possible to procure evidence of the kind, when diligently sought for. It is often too very decisive in its operation on judicial proceedings. In the case of Margaret Wishart tried at the Perth Spring Circuit in 1827 for poisoning her blind sister, a man who lodged with the prisoner and cohabited both with her and with the deceased, appeared at first from general circumstances to be implicated in the crime. He had left the house, however, on the morning of the day before that on the evening of which the deceased took ill; and he did not return till after her death. Now her illness commenced suddenly and violently; and arsenic was the poison which caused it.^[125] It was quite clear, therefore, that the poison could not have been administered, at least in a dangerous dose, so early as the day before she was taken ill; and such I stated to be my opinion, on a reference from the Lord Advocate. The evidence being also otherwise insufficient, the man was set at liberty. In the case of Mrs. Smith tried here in February of the same year, this branch of the evidence was made the subject of question under more doubtful circumstances. The deceased certainly died of poisoning with arsenic, and the prisoner was strongly suspected of being the poisoner for many reasons, and among others because, on the evening before the morning on which the deceased took ill, the prisoner gave her in a suspicious manner a white-coloured draught. Here the possibility of the draught having been the cause of the symptoms must be admitted. But as they did not appear for eight hours after the draught was taken, I stated in my evidence that it was improbable the dose, if it contained arsenic at all, contained a quantity sufficient to cause the violent symptoms and death which followed.^[126]

The correspondence in point of time between the appearance of symptoms of poisoning, and the administration of suspicious articles by an individual, constitutes still more decisive proof in a set of cases, in which it is of great value, as the chemical evidence is generally defective,—namely, where poisoning is attempted with repeated moderate doses. If the several renewals or exacerbations of illness correspond with the periods when suspicious articles have been given by the same individual, the circumstantial evidence of the administration may be even tantamount to direct proof. Thus, on the trial of Miss Blandy for the murder of her father, it was proved, that Mr. Blandy on several occasions, after the prisoner received certain suspicious powders from her lover, was taken ill with vomiting and purging; and that on two occasions recently before his death, when he got from his daughter a bowl of gruel which contained a gritty sediment, he was attacked after a very short interval with pricking and heat in the throat, mouth, stomach, and bowels,—with sickness, vomiting, gripes, and bloody diarrhœa.^[127] Here the proof of administration by the prisoner was complete.

These examples will show how the evidence of a particular person’s criminality may be affected by the relation subsisting in point of time between the commencement of the symptoms and the suspicious administration of particular articles. But farther, the special period at which the symptoms begin may even at times supply strong evidence of his instrumentality, although there may be no direct proof from general evidence of his having been concerned in administering anything whatever in a suspicious manner. This statement is well exemplified by the case of Mrs. Humphreys, who was convicted at the Aberdeen Autumn Circuit in 1830 for poisoning her husband, by pouring sulphuric acid down his throat while he was asleep. It was clearly proved, as will be seen under the head of sulphuric acid, that the deceased died of this poison; and the administration was brought home to the prisoner in the following singular manner. The only inmates of the house were the deceased, the prisoner, and a maid-servant. The deceased got a little intoxicated one evening at a drinking party in his own house; and after his friends all left the house, and the street-door was barred inside, he went to bed in perfect health, and soon fell fast asleep. But he had slept scarcely twenty minutes, when he suddenly awoke with violent burning in his throat and stomach; and he expired in great agony towards the close of the second day. Now sulphuric acid, when it occasions the violent symptoms observed in this instance, invariably excites them in a few seconds, or in the very act of swallowing. It was, therefore, impossible that the man could have received the poison at the time he was drinking with his friends; and as he knew he had not taken any thing else afterwards, and it was fully proved that he had been asleep before his illness suddenly began,—it followed that the acid must have been administered after he fell asleep, the accomplishment of which was rendered easy by a practice he had of sleeping on his back with his mouth wide open. But, after he gave the alarm, the door was found barred as when he went to bed. Consequently no one could have administered the poison except his wife or servant; and it was satisfactorily proved, that no suspicion could attach to the latter. Such was one of the principal train of circumstances, which, as it were by a process of elimination, led to the inference that the wife was undoubtedly the person who administered the poison. Other circumstances of a similar tendency were also derived from the medical evidence; but these it is unnecessary to detail at present. I have related the particulars of the whole case fully elsewhere.^[128] The prisoner strenuously denied her guilt after being sentenced, but confessed before her execution.

4. The next article in the moral evidence relates to the intent of the person who is proved to have administered poison. When the administration is proved, little evidence is in general required to establish the intent. It is sufficient that the giver knew the substance administered was of a deadly nature; and in regard to any of the common poisons this knowledge is sufficiently constituted by his simply knowing its name.

In some cases, however, the exact nature of the poison is not established with certainty; and then something else may be required to prove the prisoner’s knowledge, and through that knowledge his intent. In the case of Charles Munn, formerly alluded to [p. 50], arsenic was the poison presumed to have been taken by the deceased. But the purchase or possession of it by the prisoner was not for some time satisfactorily established; neither was there any chemical evidence, the deceased having lived forty days and upwards after taking the poison. It was proved, however, that whatever it was which had been administered, the prisoner knew very well that what he gave was deleterious; because he persuaded the deceased, who was pregnant by him, to take it by assigning to it properties which no drug either possesses, or is so much as thought by the vulgar to possess. On one occasion he persuaded her that it would show whether she was with child, and on another that it would prevent people from knowing she was with child. In such cases, then, good evidence may be derived from the arguments used by the giver to persuade his victim to take the poison; and sometimes, as in the instance now mentioned, it will lie with the medical witness to inform the court whether or not the reasons assigned are false.

Sometimes it has been pleaded by the prisoner that he gave the poison by mistake. In all such cases, if he descends to particulars, which he cannot help doing, there is every likelihood that the falsehood of the defence will be made evident by the particulars of the story not agreeing with other particulars of the moral or medical evidence. At present it is only necessary to allude to inconsistencies in his story with the medical facts. No general rules can be laid down on the method of investigating a case with a view to evidence of this kind: I must be satisfied with an illustration from an actual occurrence. On the trial of Mr. Hodgson, a surgeon, at the Durham Autumn Assizes in 1824, for attempting to poison his wife, it was clearly proved, that pills containing corrosive sublimate, and compounded by the prisoner, were given by him to her in place of pills of calomel and opium, which had been ordered by her physician. But it was pleaded by him, that, being at the time intoxicated, he had mistaken, for the shop-bottle which contained opium, the corrosive-sublimate bottle which stood next it. This was certainly an improbable error, considering the opium was in powder, and the sublimate in crystals. But it was not the only one which he alleged he had committed. Not long after his wife took ill, the physician sent the prisoner to the shop to prepare for her a laudanum draught, with water for the menstruum. When the prisoner returned with it, the physician, in consequence of observing it to be muddy, was led to taste it, before he gave it to the sick lady: and finding it had the taste of corrosive sublimate, he preserved it, analyzed it, and discovered that it did contain that poison. The prisoner stated in defence, that he had a second time committed a mistake, and instead of water had accidentally used for the menstruum a corrosive-sublimate injection, which he had previously prepared for a sailor. This was proved to have been impossible; for the injection contained only five grains to the ounce, while the draught, which did not exceed one ounce, contained fourteen grains.^[129]

I believe it must be allowed, that, as the medical inquiries preparatory to trial are commonly conducted without the inspector being made acquainted with the moral circumstances in detail, it is rarely possible for him to foresee what points should be attended to, with the view of illustrating the intent. But the case now related will show that it is impossible for him to render his inquiries too minute or comprehensive; and more particularly, it shows the propriety of ascertaining, whenever it is possible, not only the nature but likewise the quantity of the poison.