INFLUENCE OF DISEASE. 79 poisonous in the food itself; but it acts as a poison to particular personswhether from its being in these cases a poison per se, or rendered so by changes during the process of digestion, it is difficult to say. The subject of idiosyncrasy is of importance in a medico-legal view when symptoms resembling those of poisoning follow a meal consisting of a particular kind of food. In such a case, without a knowledge of this peculiar condition, we might hastily attribute to poison effects which were really due to another cause. It would appear that in some instances idiosyncrasy may be acquired―i. e., a person who, at one period of his life, had been in the habit of partaking of a particular kind of food without injury, may find at another period that it will disagree with him. When pork has been disused as an article of dietary for many years, it cannot always be resumed with impunity. In cases in which the powers of life have become enfeebled by age, the susceptibility of the system to poisons is increased; thus aged persons may be killed by comparatively small doses of arsenic and opium. In 1883, the editor found that an aged woman died narcotised after taking an opiate containing less than one grain of opium-a dose which on previous occasions she had occasionally taken with impunity. Cases of acquired idiosyncrasy are very rare: it appears to be, if we may so apply the term, a congenital condition. There are, however, certain diseases which seem to confer a power of supporting large and even poisonous doses of some substances. Very large doses of opium have been taken without producing dangerous symptoms by persons laboring under tetanus and hydrophobia. This condition is called tolerance. It has been witnessed in diseases of the lungs in reference to the use of antimonial medicines. Influence of Disease.-A diseased state of the body may render a person comparatively insusceptible to the action of certain poisons, while in other instances it may increase their action and render them fatal in small doses. In dysentery and in tetanus a person may take, without being materially affected, a quantity of opium sufficient to kill an adult in average health. In mania, cholera, hysteria, and delirium tremens, large doses of opium may be borne with comparative impunity. In a case of hemiplegia, a woman, æt. 29, took for six days three grains of strychnine daily without injurious consequences-the dose having been gradually raised (Gaz. Méd., Mai, 1845); while one grain of strychnine is commonly regarded as a fatal dose to a healthy adult. In a case of tetanus, Dupuytren gave more than two ounces of opium at a dose (60 grammes) without serious consequences: Flandin, Traité des Poisons, vol. 1, p. 231. It has also been remarked that persons affected with tetanus are not easily salivated by mercury. The morbid state appears to create the power of resisting the ordinary effects of poisons. The effect of certain diseases of the nervous system, as well as of habit, either in retarding the appearance of symptoms, or in blunting the operation of a poison, it is not difficult to appreciate; they are cases which can present no practical difficulty to a medical jurist. On the other hand, in certain diseased states, there may be an increased susceptibility of the action of poison. Thus, in those persons who have a predisposition to apoplexy, a small dose of opium may act more quickly, and prove fatal. In a person laboring under inflammation of the stomach or bowels, there would be an increased susceptibility of the effects of arsenic, antimony, and other irritants. In debility from any cause these mineral substances would also act injuriously even in ordinary doses. Antimony is a most powerful depressant, and might, by its effect on the heart, cause sudden death by syncope. The influence of disease in increasing the operation of poison has been noticed in cases of 80 CLASSIFICATION OF POISONS-IRRITANTS. diseased kidneys (granular degeneration), in which small doses of mercury have produced severe salivation, leading to exhaustion and death. In diseases of the lungs affecting aged persons, opium in medicinal doses has been observed to exert a poisonous action. The effect of the drug appears to be intensified by the disease. This observation applies equally to morphine. A fatty condition of the muscular tissue, leading to great feebleness of the heart's action, appears to be highly favorable to death by syncope under the use of chloroform. A knowledge of these facts is of importance in reference to charges of malapraxis when death has arisen from ordinary or extraordinary doses of medicines administered to persons laboring under disease. In such cases another mode of treatment should be substituted, or a smaller dose than usual given, and its effects carefully watched. In some instances, however, full and large doses of powerful drugs have been recklessly given, and when a fatal result has followed, there has been a strong disposition to refer death to the supposed disease, of which, however, sometimes no trace could be found in the body. CLASSIFICATION OF POISONS.-Poisons may be divided into two classes, according to their mode of action on the system; namely, IRRITANTS and NEUROTICS, as the special action of the latter is to affect directly one or more parts of the nervous system. No quite satisfactory classification has, however, been hitherto proposed. IRRITANTS. The irritants are possessed of these common characters. When taken in ordinary doses, they occasion speedily violent vomiting and purging. The symptoms are either accompanied or followed by pain in the stomach and bowels. The peculiar effects of the poison are manifested chiefly on these organs, which, as their name implies, they irritate and inflame. Many substances belonging to this class of poisons possess corrosive properties; such as the strong mineral acids, caustic alkalies, bromine, corrosive sublimate, and others. These, in the act of swallowing, are commonly accompanied with an acrid or burning taste, extending from the mouth down the gullet to the stomach. Some irritants do not posses any corrosive action-of which we have examples in white arsenic, the poisonous salts of barium, carbonate of lead, and cantharides; these are often called pure irritants. They exert no destructive chemical action on the tissues with which they come in contact; they simply irritate and inflame them. Difference between Corrosive and Irritant Poisons. As a result of the action of corrosive poisons, symptoms are commonly manifested immediately, because mere contact produces the destruction of a part. In the action of the purely irritant poisons, the symptoms are generally more slowly manifested, rarely showing themselves until at least half an hour has elapsed from the time of swallowing the substance. Of course, there are exceptions to this remark; for sometimes irritants act speedily, though rarely with the rapidity of corrosive poisons. It is important in a practical view to ascertain whether, in an unknown case, the poison which a person requiring immediate treatment may have swallowed is irritant or corrosive. This may be commonly determined by a knowledge of the time at which the symptoms appeared after the suspected substance was taken. We may thus often easily distinguish between a case of poisoning from arsenic and one from corrosive sublimate. There is also another point which may be noticed. As the corrosive substance exerts a local chemical action, an examination of the mouth and throat may enable us in some cases to solve the question. It has already been stated that there are many irritant poisons which have no corrosive properties, but every corrosive may act as an irritant. Thus the action of corrosive sublimate is that of an irritant poison, as, while it destroys some parts of the coats of the stomach and intestines, it irritates and imflames others. So, again, most corrosive poisons may lose their corrosive properties by dilution with water, and they then act simply as irritants. This is the case with the mineral acids and bromine. In some instances it is not easy to say whether an irritant poison possesses corrosive properties or not. Thus oxalic acid acts immediately, and blanches and softens the mucous membrane of the mouth and throat, but it is comparatively rare to meet with any decided marks of chemical corrosion produced by it in the stomach or viscera. Irritant poisons, for the most part, belong to the mineral kingdom; and they may be divided into the Non-Metallic and Metallic Irritants. There are a few derived from the animal and vegetable kingdoms; but these, if we except cantharides, are not often employed criminally. Some of the gases likewise belong to the class of irritant poisons. NEUROTICS.-Neurotic poisons act upon the nervous system. Either immediately or some time after the poison has been swallowed, the patient suffers from headache, giddiness, numbness, paralysis, stupor, or convulsions. They have not an acrid burning taste like the corrosive irritants; and they rarely give rise to purging. When vomiting or purging follow the ingestion of the poison into the stomach, the effects may be generally ascribed either to the form or quantity in which it has been taken, and the mechanical effect on the stomach thereby produced, or to the poison being combined with some irritating substance. The pure narcotics, or cerebral poisons, are not found to irritate or inflame the stomach and bowels. Notwithstanding the well-defined boundary thus apparently existing between these classes of poisons, it must not be supposed that the substances arranged in each class always act in the manner indicated. Some irritants have been observed to affect the brain or the spinal marrow, and this may be either a primary or secondary consequence of their action. Arsenic and oxalic acid, although classed as irritants, have in some instances given rise to symptoms closely resembling those of narcotic poisoning; namely, coma, paralysis, and tetanic convulsions. In a case of poisoning by arsenic, which occurred to Morehead, the symptoms of narcotism were so strongly marked that it was believed at first the man had taken a narcotic: Med. Gaz., vol. 43, p. 1055 A case has been met with of poisoning by arsenic in which there was paralysis of the limbs, with an entire absence of purging during the eight days that the deceased survived. On the other hand, in a case of poisoning by a large dose of opium, there was an absence of the usual symptoms of cerebral disturbance, and the presence of others resembling those of irritant poisoning— namely, pain and vomiting. Thus, then, we must not allow ourselves to be misled by the idea that the symptoms are always clearly indicative of the kind of poison taken. The narcotic or cerebral poisons belong mostly to the vegetable kingdom. Some of the poisonous gases possess a narcotic action. Some poisons have a complex action. They are chiefly derived from the vegetable kingdom. At variable periods after they have been swallowed, they give rise to vomiting and purging, like irritants; and sooner or later produce stupor, coma, paralysis, and convulsions, owing to their effects on the brain and spinal marrow. In the state of vegetables, as leaves, seeds, or roots, they possess the property, like irritants, of irritating and inflaming the stomach and bowels. As familiar examples we may point to nux vomica, aconite, hemlock, and poisonous mushrooms. These 82 EVIDENCE OF POISONING IN THE LIVING. poisons are very numerous, embracing a large variety of well-known vegetable substances; but they rarely form a subject of difficulty to a medical practitioner. The fact of the symptoms occurring after a meal at which some suspicious vegetables may have been eaten, coupled with the nature of the symptoms themselves, will commonly indicate the class to which the poison belongs. Some of these poisons have a hot acrid taste; others, like aconite, produce a sense of numbness or tingling; while others again have an intensely bitter taste, as nux vomica, strychnine, veratrine, and picrotoxin. Strychnine may be regarded as a pure spinal poison. In the description of poisons no systematic classification can be consistently followed. CHAPTER V. EVIDENCE OF POISONING IN THE LIVING BODY.-SYMPTOMS CONNECTED WITH FOOD OR MEDICINE. SEVERAL PERSONS ATTACKED SIMULTANEOUSLY.—EVIDENCE FROM THE DETECTION OF POISON IN THE FOOD. WE now proceed to consider the evidence of poisoning in the living body. To the practitioner the diagnosis of a case of poisoning is of great importance, as, by mistaking the symptoms produced by a poison from those arising from natural disease, he may omit to employ the proper remedial measures, and thus lead to the death of the patient. To a medical jurist a correct knowledge of the symptoms furnishes the chief evidence of poisoning, in those cases in which persons are charged with the malicious and unlawful administration of poison. The symptoms produced during life constitute also an important part of the evidence in those instances in which a poison proves fatal. At present, however, we will suppose the case to be that poison has been taken and the patient survives. Most toxicological writers have laid down certain characters whereby it is said symptoms of poisoning may be distinguished from those of disease. 1. In poisoning, the symptoms appear suddenly, while the individual is in health. It is the common character of most poisons, when taken in the large doses in which they are usually administered with criminal intent, to produce serious symptoms, either immediately or within a very short period after they had been swallowed. Their operation, under such circumstances, cannot be suspended, and the symptoms are then manifested after an indefinite interval; although the contrary was formerly a matter of universal belief, and gave rise to many absurd accounts of what was termed slow poisoning. The symptoms of poisoning by nicotine, prussic acid, oxalic acid, or the salts of strychnine, appear immediately, or generally within a very few minutes after the poison has been swallowed. In an exceptional case, in which the dose of prussic acid was small, and insufficient to produce death, the poison was supposed by the patient not to have begun to act until after the lapse of fifteen minutes: Ed. Med. and Surg. Jour., vol. 59, p. 72. The symptoms caused by arsenic and other irritants, and, indeed, by poisons generally, are commonly manifested in from half an hour to an hour. It is rare that the appearance of symptoms is protracted for two EVIDENCE OF POISONING FROM SYMPTOMS. 83 hours, except under certain peculiar states of the system. It is said that some neurotic poisons, such as the poisonous mushrooms, may remain in the stomach twelve or twenty-four hours without giving rise to symptoms; and this is also affirmed to be the case with some animal irritants, such as decayed meat; but with regard to mushrooms, it has been shown by Peddie that they have produced symptoms in half an hour; and a case fell under the author's own observation in which the symptoms from noxious animal food came on within as short a time after the meal as is commonly observed in irritant poisoning by mineral substances. In some cases of poisoning by phosphorus, no obvious symptons have occurred until after the lapse of some days. 2. Symptoms appear during a state of health.-Symptoms of poisoning may manifest themselves in a person while in a state of perfect health, without any apparent cause. This rule is, of course, open to numerous exceptions, because the person on whose life an attempt has been made may be actually laboring under disease; and under these circumstances, the symptoms may be so obscure as often to disarm all suspicion. When poison is secretly given in medicine, a practitioner is very liable to be deceived, especially if the disease under which the person is laboring is of an acute nature, and is attended with symptoms of disorder in the alimentary canal. Several cases of poisoning have occurred in which arsenic was criminally substituted for medicine, and given to the person while laboring under a disorder of the bowels. We are, however, justified in saying, with respect to this character of poisoning, that when, in a previously healthy person, violent vomiting and purging occur suddenly and without any assignable cause, such as disease, indiscretion in diet, or pregnancy, to account for them, there is reason to suspect that irritant poison has been taken. When the patient is already laboring under disease, we must be especially watchful of the occurrence of any sudden change in the character or violence of the symptoms, unless such change can be easily accounted for on well-known medical principles. In most cases of criminal poisoning we meet with alarming symptoms without any obvious or sufficient natural causes to explain them. The practitioner will, of course, be aware that there are certain diseases which are liable to occur suddenly in healthy people, the exact cause of which may not at first sight be apparent; therefore this criterion is only one out of many on which a medical opinion should be founded. 3. In poisoning the symptoms appear soon after a meal, or soon after some kind of food or medicine has been taken. This is by far the most important character of poisoning in the living body. It has been already stated that most poisons begin to operate within about an hour after they have been swallowed; and although there are a few exceptions to this remark, yet they occur under circumstances easily to be appreciated by a practitioner. Thus, then, it follows that, supposing the symptoms under which a person is laboring to depend on poison, the substance has most probably been swallowed, either in food or medicine, from half an hour to an hour previously. It must be observed, however, that cases may occur in which the poison has not been introduced by the mouth. Oil of vitrol and other corrosive liquids have been thrown up the rectum in enemata, and have thus caused death; the external application of arsenic, corrosive sublimate, and cantharides to ulcerated surfaces has destroyed life. In one case arsenic was introduced into the vagina of a female, and she died in five days under all the symptoms of arsenical poisoning: Schneider, Ann. der Ges. Staatsarzneikunde, i. 229. Such cases are rare, but, nevertheless, the certainty that they have occurred, where their occurrence could |