Page:Treatise on poisons in relation to medical jurisprudence, physiology, and the practice of physic (IA treatiseonpoison00chriuoft).pdf/591

 of its action on the brain. Its action on both is clearly indicated by the combination of coma with tetanus. The independent action on the spine is well shown by the following experiment of Wedemeyer. In a dog the spinal cord was divided at the top of the loins, so that no movement took place when the hind-legs were pricked: hydrocyanic acid being then introduced into a wound in the left hind-leg, symptoms of poisoning commenced in one minute, and the hind-legs were affected with convulsions as well as the fore-legs.

Hydrocyanic acid affects all animals indiscriminately. From the highest to the lowest in the scale of creation all are killed by it; and all perish nearly in the same manner. Such is the result of a very extensive series of experiments by Coullon.

It is scarcely necessary to observe that hydrocyanic acid acts energetically as a poison, through whatever channel it is introduced into the body. Whether it be swallowed, or injected into the rectum, or dropped into the eye, or applied to a fresh wound, or inhaled in the form of vapour, its action is exerted with tremendous energy. Perhaps it may even act through the sound skin. It has not, hitherto, indeed, been found to affect animals in this way, evidently because their skin is too thick and impermeable. But M. Robiquet informed me that once, while he was making some experiments on the tension of its vapour, his fingers, after being some time exposed to it, became affected with numbness, which lasted several days; I have repeatedly remarked the same effect when handling tubes which contained the concentrated acid; and Emmert found that the essential oil of bitter almond, applied to the uninjured skin of the back of a rabbit, produced the usual symptoms and death: and that the peculiar odour of the poison was quite distinct after death in the deep-seated muscles of the back.

This substance is poisonous in all its chemical combinations. Coullon remarked that two drops of the hydrocyanate of ammonia killed a sparrow in two minutes. Robiquet and Magendie found that a hundredth part of a grain of the cyanide of potassium killed a linnet in thirty seconds, and five grains a large pointer in fifteen minutes; Orfila has related an instance of death in the human subject within an hour after the administration of six grains of cyanide of potassium in an injection; and in a recent experimental investigation the same author found that this salt produces all the effects of hydrocyanic acid. Schubarth killed a dog in twenty minutes with twenty drops of the diluted acid neutralized by ammonia, and another in three hours with twenty-five drops neutralized by potass. These facts are a sufficient answer to a statement made by Mr. Murray of London, to the effect, that a considerable dose of the acid