1. Pure strychnia is not changed in color when treated with iodic acid or with either of the strong mineral acids; but as this alkaloid generally contains brucia, nitric acid reddens it.
2. Dissolved in sulphuric acid no change ensues; but on adding a fragment of bichromate of potass to the solution a series of blue, violet, purple and red tints are produced. The same result is brought about by using ferricyanide of potassium, permanganate of potassium, the peroxide of lead, or the black oxide of manganese.
3. If the skin of a frog be dried, and a few drops of a solution containing strychnia applied to it, strong tetanic convulsions will ensue, and be reproduced every time the animal is touched or irritated. According to Dr. Marshall Hall this strychnoscopic test will detect the 1/5000th of a grain, or even less.
4. An exceedingly useful class of tests for many poisons has been introduced by Dr. Guy; we mean the crystalline appearances presented on subliming the substance and condensing it on a cool microscopic slide, or the crystalline form observed as modified by various reagents. Thus the strychnine sublimate, touched with a drop of carbazotic acid, forms groups of arborescent crystals, each branch forming part of a circle, when seen under the microscope.
ACONITE (_Aconitum Napellus_, _Monkshood_, _Wolfsbane_, _Blue Rocket_).—This beautiful plant is found in most parts of Europe.
_Aconitia_, the alkaloidal base of the plant, is the most deadly poison known; the fiftieth part of a grain having nearly caused death.
The chief _symptoms_ of poisoning by aconite are numbness and tingling in the mouth and throat, giddiness, abolition of muscular power, pain in the abdomen, with vomiting and purging. Sometimes delirium and slight stupor have been noticed. The pupils are usually dilated, the skin is cold, the pulse exceedingly feeble, the breathing oppressed, and there is a dread of approaching dissolution. Frequently the sufferer is perfectly conscious, though paralyzed, till death suddenly occurs after two or three hurried gasps. According to Dr. Fleming, death may be due to a sedative impression on the nervous system, or to asphyxia from paralysis of the respiratory muscles, or to syncope.