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. CHAPTER XXVII. HYPOSTHENISANTS. NEUROTICS PRODUCING DEATH BY SYNCOPE. ACONITE—PRUSSIC ACID. 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. A fatal mistake is not very uncommonly made in eating the root of aconite for that of horseradish. The sense of tingling and numbness produced by the former is so different from the pungent taste of the latter that with due care no mistake should occur, except the plants be allowed to grow together, which should never be done. A case occurred in Ireland where a woman poisoned one man and nearly killed another by sprinkling powdered aconite root over a dish of greens. Of the root one drachm, of the tincture one drachm, and of the alcoholic extract four grains, have caused death. Death follows a considerable dose in less than an hour, but sometimes a longer period elapses. The Bikh poison, formerly much used in India, and still not unfrequently employed, has as its basis the Aconitum ferox, a still more dangerous drug than our indigenous plant. _Treatment._—No time must be lost in the use of remedies. In addition to emetics, castor oil, and animal charcoal, benefit may be derived from administering strong coffee. Brandy or ammonia should also be given, while the limbs and back are well rubbed with hot towels. Artificial respiration might prove useful.