TOXICOLOGY

(Gr. toIikov, poison, and \oyos, a discourse.) Poisons have been divided by Orfila ami Christ is on into irritants, narcotics, and narcotico-acrids: the first cla including those whose sole or predominating symptoms are those of irritation or inflammation; the second, those which produce stupor, delirium, and other affections of the brain and nervous system; and the third, those which are of a mixed character. The chief effects of irritants are upon the alimentary canal, exciting inflammation, and sometimes ulceration of the tongue, fauces, and oesophagus, difficult deglutition, nausea, vomiting, and heat and pain of the stomach, with more or le tension of the abdomen, and pain on pre ure. The sickne is generally accompanied by extreme anxiety and anguish, and the matters vomited consist, in the first in stance, of any food that may have been in the stomach, with portions of the poison itself, and afterwards of viscid mucus, often streaked with blood and tinged with bile; the pain afterwards extends throughout the intestines, and mucous, bilious, and often bloody diarrhoea succeeds. The skin is cold and clammy, the pulse quick and feeble, the breathing often difficult, and the countenance expre ive ot extreme anxiety. JVarcotic poisons induce a train of symptoms of a very distinct character: headach, vertigo, confused vision, stupor convulsions, paralysis, and coma, are their leading el: but each particular poison is usually attended by certain peculiarities in the succe ion, violence, or generic character of the symptoms, which a ist the experienced practitioner not only in determining the nature of the poison, brt in discriminating between its effects and those of disease. The symptoms of the narcotico-acrid poisons usually consistot those of the two former cla es blended, and are of ten of a Very complicated character; for the most part, however, their narcotic and irritant effects appear to be incom patible. In large doses, narcotic ism predominates; in small er, irritation: it is rarely that both are coexistent. In the following tabular view of the principal poisons i the above cla es, they are enumerated in the order in whicl they are described by Dr. Christ is on, to whose Treatise on Poisons the reader is referred for details which would be quite incompatible with the space which can be allotted the subject in this work. Under the heads, however, < many of the individual substances mentioned in the follow ing list, we have elsewhere given particulars respect i i their composition and properties, and sometimes referred to their toxicological history. I. Irritant Poisons. Mineral acids. Arsenic and its compounds Phosphorus. Mercurial compounds Acetic acid. Salts of copper. Oxalic acid. Antimonial poisons Fixed alkalies. Salts of tin. Nitre. Salts of gold. Alkaline and earthy chic- Salts Salts of of bismuth silver. Lime.rides. Salts of chromium Ammonia and its salts. Salts of zinc. Alkaline sulphurets. Lead poisons. Barytes. Diseased and decayed animal matter. Cantharides.Vegetable acrids. Mechanical irritants Venomous serpents. IJ. Narcotic Poisons. Carb azotic Hydrocyanic acid.acid. Opium. Lactuca.Hyoscyamus. Poisonous gases. Solatium. NARCOTICO-ACRln [s. 1270]