Page:Treatise on poisons in relation to medical jurisprudence, physiology, and the practice of physic (IA treatiseonpoison00chriuoft).pdf/464

 *ing part of the latter species in a toxicological point of view is the root; the juice of which is a most energetic poison. The Janipha manihot, or cassava-plant, has two varieties, one of which produces a small, spindle-shaped, bland root, called, in the West Indies, sweet cassava, while the other has a much larger, bitter, poisonous root, called bitter cassava, and in universal use for obtaining the well-known amylaceous substance, tapioca. The juice of the bitter variety is watery, and so poisonous that, according to Dr. Clark of Dominica, negroes have been killed in an hour by drinking half a pint of it. It has been commonly, but erroneously, arranged among acrid poisons. It really belongs to the narcotic class, for it occasions coma and convulsions. And we now know the cause of this extraordinary anomaly in the natural family to which the species belongs; because MM. Henry and Boutron ascertained that the juice imported into France, as well as what they expressed from fresh roots sent from the West Indies, contains hydrocyanic acid, produces in animals all the usual effects of that poison, and is rendered inert by such means as will remove the acid,—for example, by the addition of nitrate of silver. I confirmed this singular discovery in 1838 by examination of some well-preserved juice from Demerara. It is easy to see how tapioca, which is obtained from the poisonous root by careful elutriation, becomes quite bland during the process. Of Poisoning with Manchineel.

The manchineel [Hippomane mancinella], another plant of the same natural family, contains a milky juice, which is possessed of very acrid properties. Orfila and Ollivier have made some careful experiments with it on animals, and M. Ricord has since added some observations on its effects on man. From the former it appears that two drachms of the juice applied to a wound in a dog will cause death in twenty-eight hours, by exciting diffuse cellular inflammation; and that half that quantity will prove fatal in nine hours when introduced into the stomach. From the observations of M. Ricord it follows that inflammation is excited wherever the juice is applied, even in the sound skin; but he denies the generally received notion, that similar effects ensue from sleeping under the branches of the tree, or receiving drops of moisture from the leaves. This notion, however, it is right to add, has been adopted by other recent authors. Descourtils, for example, states that it is dangerous to sleep under the tree; that drops of rain from the leaves will blister any part of the skin on which they fall; and that on these accounts the police of St. Domingo were in the practice of destroying the trees wherever they grew. Other species of Hippomane are equally poisonous. The H. biglandulosa and H. spinosa are peculiarly so, especially the latter,