b. Narcotics and Sedatives.—These poisons affect primarily the nervous system, and through that, the circulation; producing stupor, stertorous breathing, depression of the heart, lividity of the face, and in some instances convulsions and delirium. The narcotico-acrids possess also irritating qualities, and such are attended with the burning sensations in the throat and fames peculiar to the irritant poisons; if these sensations be followed by the supervention of nervous symptoms, the diagnosis is com paratively easy. In poisoning by the simple narcotics there may be more difficulty in arriving at a diagnosis. Opium produces stupor, somnolence with contracted pupils, and coma. This order of sequence is the best aid to diagnosis, especially in the absence of convulsions: the same order is also observed in cases of albu minuria : but the symptoms come on more slowly, occupying days in place of hours, except when the coma is hastened by convul sions, which are very common among the head symptoms in Bright's disease, and are exceedingly rare in narcotic poisoning. This order is exactly reversed in another class of cases, which commence with convulsion and terminate with prolonged stupor; we shall have occasion to refer to those in speaking of serous and transient apoplexy. If the history be unknown, as in a patient brought from the street, there are points of time in which the symptoms of the two states closely correspond; the probable duration must here be taken into account, and the rapid or gra dual development of the symptoms. When, from circumstances, it appears probable that the seizure has been sudden, a condition of drowsiness, partial stupor, and unwillingness to move, must not be taken as conclusive of poisoning by opium. We must refer to the state of the pupils, which in the functional disorder are seldom contracted, as they are in the cases of narcotic poisoning; the condition of the mental faculties also aflOrds aid in diagnosis, as they are nearly natural when the patient is roused from the state of narcotism: while there is great confusion, perhaps com plete unconsciousness, of surrounding objects and circumstances, in one who is suffering from epileptic sopor.
At a further stage the complete coma may closely resemble sanguineous apoplexy. Here we have regard to the suddenness of the seizure, the existence of any degree of consciousness, and the absence or presence of paralysis. If the patient can be roused at all, and there be no paralysis, the probability is in favor of poisoning by opium; if the seizure appear to have been sudden, in favor of apoplexy. Equal contraction of both pupils points to poisoning, unequal contraction or dilatation to apoplexy. Intoxication, when of such a degree as to be classed among cases of narcotic poisoning, may generally be distinguished by the odor of the breath.
Hydrocyanic acid is extremely sudden in its action; there is less of coma and more of convulsion accompanying the condition of unconsciousness. It very often reveals itself by its powerful odor.
The poison of ‘strychnia is easily recognized by its violent tetanic spasms when occurring in a person who has not been previously ailing, and who exhibits no wound or injury to which tetanus could be attributed. Belladonna, hyoscyamus, and others of the same class, are generally accompanied by symptoms of delirium; and in some instances a cutaneous eruption, somewhat resembling urticaria, has been observed. The extreme dilatation
of the pupil by the solanacea3 contrasts strikingly with its con traction by opium.
c. The gaseous poisons, while they oppress the brain, producing chiefly a comatose state, also prevent the proper oxygenation of the blood, and are therefore specially marked by lividity of face. The place where the person is found, and the sense of suffocation experienced by those who attempt to rescue him, seldom leave any room for doubt.
d. Slow Poisoning.—Attention has recently been revived to this mode of the employment of poisons, because of the suspicion that it has been carried to a fatal issue, in more than one instance, with impunity. It was supposed to have been very generally practised by the poisoners of former ages; but the light of science has shown how very few of the poisons can be so used, and bow very readily they may be detected, if suspicion be only awakened. Antimony and arsenic are those which have been recently em ployed; the former may be very readily disguised ; the latter requires more ingenuity for its concealment. One of the most striking features of the cases recorded was the entire cessation of the symptoms in the absence of a particular member of the family; and such a coincidence ought, of course, to arrest our attention. In the employment of antimony many symptoms must be wanting which ought to be found in any condition of stomach that could otherwise account for the constant vomiting and extreme depres sion. By arsenic, again, ulceration of the bowels is actually pro duced, and, therefore, the absence of general indications is not so distinctive; but the medical attendant may be aroused by the presence of some particular symptoms, such, for instance, as tingling sensations in the hands, which are recorded as among its more constant concomitants.
Vegetable poisons have not been, and perhaps cannot be, thus employed. When introduced in small quantity, they appear either to be decomposed or to pass out of the body without exerting their poisonous influence, while the system gets accustomed to their presence, and tolerates them 'in larger doses. One remarkable exception to this is found in digitalis, which, by its continued administration, acquires a cumulative power, suddenly acting as a poison when given for a time as a medicine. Its effects then resemble an ordinary case of poisoning by digitalis, and present nothing remarkable in consequence of the slowness of its intro duction.
The subject of slow poisoning, as it has received little atten tion, requires at present further study. It affords an illustration of what has been so often urged, that in every case our judgment must not be based on the evidence of one single fact. The pre sence of the poison in the body, without its usual symptoms, except when found in a poisonous quantity in the stomach itself, is as unsatisfactory, in a case of sudden death, as the detail of ill defined symptoms without the discovery of the poison in a case of slow poisoning: whereas, a definite group of symptoms may be enough to outweigh the negative evidenc,e that chemistry has failed to find the foreign substance in the stomach or the tissues.