IV.—The Strychnine or Tetanus-Producing[422] Group of Alkaloids.

[422] To this group also belong some of the opium alkaloids. See “[Thebaine],” “[Landamine],” “[Codeine],” “[Hydrocotarnine].”

1. NUX VOMICA GROUP—STRYCHNINE—BRUCINE—IGASURINE.

§ 385. Nux vomica is found in commerce both in the entire state and as a powder. It is the seed of the Strychnos nux vomica, or Koochla tree. The seed is about the size of a shilling, round, flattened, concavo-convex, of a yellowish-grey or light-brown colour, covered with a velvety down of fine, radiating, silky hairs, which are coloured by a solution of iodine beautiful gold-yellow; the texture is tough, leathery, and not easily pulverised; the taste is intensely bitter. The powder is not unlike that of liquorice, and, if met with in the pure state, gives a dark orange-red colour with nitric acid, which is destroyed by chloride of tin; the aqueous infusion gives a precipitate with tincture of galls, is reddened by nitric acid, and gives an olive-green tint with persulphate of iron. The best method, however, of recognising quickly and with certainty that the substance under examination is nux vomica powder, is to extract strychnine from it by the following simple process:—The powder is completely exhausted by boiling alcohol (90 per cent.), the alcoholic extract evaporated to dryness, and then treated with water; the aqueous solution is passed through a wet filter, and concentrated by evaporation to a small bulk. To this liquid a drop or so of a concentrated solution of picric acid is added, and the yellow precipitate of picrates thus obtained is separated, treated with nitric acid, the picric acid removed by ether, and the pure alkaloid precipitated by soda, and shaken out by chloroform.

§ 386. Chemical Composition.—Nux vomica contains at least four distinct principles:—

§ 387. Strychnine (C21H22N2O2) is contained in the bean of S. ignatius, in the bark (false angustura bark) and seeds of the Strychnos nux vomica, in the Strychnos colubrina, L., in the Strychnos tieuté, Lesch, and probably in various other plants of the same genus.