_Nicotin_, the alkaloid of tobacco, is as deadly a poison as prussic acid. It is an acrid, volatile, oily liquid, of a pale amber color. In 1858 a chemist of rising reputation committed suicide with this substance. He was seen by one of the attendants at the Museum in Jermyn Street, in the act of falling forwards out of a water-closet in which he had concealed himself. The attendant raised him up, and with the aid of another man endeavored to carry him to a table, but he heaved a deep sigh and died in their arms. The appearances afterwards found were great congestion of the membranes of the brain and a dark fluid state of the blood. The only other case of importance on record was the occasion of the _cause célèbre_ Bocarmé. This man, a Belgian count, studied chemistry, apparently, with a view to the preparation of this substance, made it in quantity, and with the help of his wife poisoned her brother. The count was condemned and executed. M. Stas was engaged to search for the poison, and thus was introduced his process, so often referred to. CONIUM (_Conium maculatum_, _Common or Spotted Hemlock_).—This indigenous plant, which grows abundantly in hedges and wild places, belongs to the order Umbelliferæ. The following common umbelliferous plants are likewise poisonous: viz., the _Cicuta virosa_ or water-hemlock, the roots of which have been eaten in mistake for parsnips; the _Œnanthe crocata_, or the water-dropwort, one of the most virulent of English vegetables; the _Æthusa cynapium_, or fool’s parsley, sometimes gathered in mistake for parsley; and the _Phellandrium aquaticum_, or fine-leaved water-hemlock, popularly known as water-parsnip. They have all given rise to accidents. The seeds, leaves, and root of the _Conium maculatum_ are all poisonous. The effects are rather variable, sometimes consisting chiefly of delirium, stupor, coma, and convulsions; on other occasions, the action, being chiefly exerted on the spinal cord, gives rise to gradually extending paralysis, the lower limbs being first affected, afterwards the arms and chest, thus producing death by apnœa from paralysis of the muscles of respiration. Probably, however, could artificial respiration be kept up, the heart would continue to beat much longer. The alkaloid of hemlock is a pale yellow, volatile, acrid oily-looking liquid, known as _conia_, _conein_ or _conicina_. It is a potent poison, occasioning general paralysis without loss of sensibility. This alkaloid, which is found in all parts of the plant, may be readily recognized by rubbing with caustic potass. This sets free the alkaloid from its combination, and being readily volatile its mouse-like odor becomes at once apparent. Chemically it is allied to ammonia, and gives many of the reactions of that substance. In many respects _curare_ (referred to under _Nux vomica_) acts similarly to _conia_.