STROPHANTHUS, a genus of plants of the natural order Apocynem, deriving its name from the long twisted thread-like segments of the corolla, which in one species attain a length of 12 or 14 inches. The genus at present comprises about 18 species; confined to tropical Africa and Asia, only one species, indigenous to the former continent, being known outside the tropics. Several of the African species furnish the natives of the countries in which they grow with the principal ingredient in their arrow poisons. The in& or onaye poison of the Gaboon, the kombe accurately known. There is little doubt, however, that S. ltispidus, D.C., is the one most frequently employed.
Two of the arrow poisons have been chemically and physiologically examined. The kombe poison was subjected to some preliminary experiments in 1862 by Prof. Sharpey, but was more fully examined a few years subsequently by Prof T. R. Fraser. From the investigations of the latter' it appears that the kombe arrow poison, when given in fatal doses, paralyses the action of the heart. In minute doses, however, it possesses a tonic action on that organ. Since the practical value of strophanthus as a medicinal agent has been pointed out by Prof. Fraser, it has been used with considerable success in some forms of heart-disease. The chemical examination showed that its activity is due to a glucoside, which has been named strophanthin. The wanika arrow poison has been examined physiologically by Dr Sydney Ringer and chemically by Mr A. W. Gerrard. Its active principle, a glucoside, was found to resemble strophanthin in its action. Chemically also, as obtained by Mr Gerrard, it seems 63 be identical with strophanthin.2 It is soluble in alcohol and water, but insoluble in ether and chloroform ; it evolves ammonia when heated with soda-lime, but gives only a slight brown coloration when treated with strong sulphuric acid.
Both S. hispidus and S. Kombe have hairy seeds with a slender thread-like appendage, terminating in a feathery tuft of long silky hairs, the seeds of the former being coated with short appressed brown hairs, and those of the latter with white hairs ; but in the species used at Delagoa Bay and called " unitsuli " the thread-like appendage of the seed is absent. According to information furnished by Messrs T. Christy & Company of London, and obtained from a correspondent on the Zanzibar coast, the natives pound the seeds into an oily mass, which assumes a red colour, portions of this mass being smeared on the arrow immediately behind the barb.
See 'cones Plantarum, No. 4, 1870; Telikan, Arch. Gen. de Nefclicine, July 1805, p. 115; Van Haaselt, Arch. Neer:. des Sc., , vii., 1875, p.161; Arch. de Physiol., No. 5, 1872, p. 526; Rapport our l'Inaye, Pavia, 1877, 8vo.