_Tests._--With nitrate of silver a white precipitate, insoluble in cold, but soluble in boiling, nitric acid. The precipitate heated, evolves cyanogen, having an odour of peach-blossoms, and burning, when lighted, with a pink flame. Liquor potassae and sulphate of iron give a brownish-green precipitate, which turns to Prussian blue with hydrochloric acid. Liquor potassae and sulphate of copper give a greenish-white precipitate, becoming white with hydrochloric acid. Sulphide of ammonium gives sulpho-cyanide of ammonium. This develops a blood-red colour with perchloride of iron, bleached by corrosive sublimate. XLII.--ACONITE =Aconite= (_Aconitum Napellus_, monkshood).--Root and leaves. Poisonous property depends upon an alkaloid, aconitine. Aconite is one of the constituents of St. Jacob's Oil. _Symptoms._--Numbness and tingling in mouth, throat, and stomach, giddiness, loss of sensation, deafness, dimness of sight, paralysis, first of the lower and then of the upper extremities, vomiting, and shallow respiration. Pupils dilated. Pulse small, irregular, finally imperceptible. The mind remains unaffected. Death often sudden. _Post-Mortem Appearances._--Venous congestion, engorgement of brain and membranes. _Treatment._--Emetics, stimulants freely. Best antidote is sulphate of atropine, 1/50 grain hypodermically, and also strychnine. Digitalis also useful. Warmth to whole body. Patient to make no exertion. _Fatal Dose._--Of root or tincture, 1 drachm. _Fatal Period._--Average, less than four hours. _Method of Extraction from the Stomach, etc._--Extraction from contents of stomach by Stas-Otto process. It may be found in the urine; gives usual alkaloidal reactions, but no distinctive chemical test known. _Tests._--Chiefly physiological; tingling and numbness when applied to tongue or inner surface of cheek. Effects on mice, etc. A cadaveric alkaloid or ptomaine has been found in the body, possessing many of the actions of aconitine. The presence of this substance was suggested in the Lamson trial. The Indian aconite, _Aconitum ferox_, the Bish poison, is much more active than the European variety. It contains a large proportion of pseudaconitine, and is frequently employed in India, not only for the destruction of wild beasts, but for criminal purposes. =Aconitine= varies much in activity according to its mode of preparation and the source from which it is derived. The most active kind is probably made from _A. ferox_. XLIII.--DIGITALIS All parts of the plant _Digitalis purpurea_ (purple foxglove) are poisonous. Contains the glucoside digitalin and other active principles. _Symptoms._--Nausea, vomiting, purging, and abdominal pains. Vomited matter grass-green in colour. Headache, giddiness, and loss of sight; pupils dilated, insensitive; pulse weak, remarkably slow and irregular; cold sweat. Salivation occasionally, or syncope and stupor. Death sometimes quite suddenly.