The organic constituents of plants and vegetable substances and their chemical analysis / by G.C. Wittstein ; authorised translation from the German original, enlarged with numerous additions, by Baron Ferd. von Mueller.

Georg Christian Wittstein

Date:: 1878

Credit: The organic constituents of plants and vegetable substances and their chemical analysis / by G.C. Wittstein ; authorised translation from the German original, enlarged with numerous additions, by Baron Ferd. von Mueller. Source: Wellcome Collection.

249/358

$hard at —27°, dries better at the air than linseed oil, yields like this soft soaps. .\anthin, according to Higgin. In the root of Rubia tinctorum. Precipitate the fresh, filtered infusion of madder with acetate of lead, wash the deposit, decompose with sulphuret of hydrogen and boil the sulphide of lead with water. The solutions, after they have been neutralised ^vith ammonia and digested with a little hycb-ated alumina, which deposit alizarin and rubiacin, yield the Xantliin on evaporating the filtrate and on extracting the residue. (By this method are obtained, according to Schunck, rubian and products of decomposition of the latter).—Dark-brown, deliques- cent, gummous body, bitter (neither acerb nor sweet), fuses and decomposes in higher temperatures, dissolves readily in water with a beautiful yellow colour, also readily in alcohol, little in ether, in alkalies with purple-red hue. The aqueous solution is precipi- table by alum and by subacetate of lead, but not by acetate of lead. Xailtll0rliamiiin=C46 Hqs O2S + 10 HO, according to Gellatly. In the matured grains of Avignon (from Rhamnus infertorius and some other congeners), or, according to Kane, a decomposition- product of the chrysorhamnin of the unripe berries. After boiling the unripe berries with water for a few minutes and drying, no chrysorhamnin is obtained, but in its stead Xanthorhamnin, Like- wise Xanthorhamnin is obtained from chrysorhamnin by boiling the latter with water under access of air. Gellatly boils the unripe pul- verised berries with alcohol, frees the not too much concentrated tincture from a slowly forming dark-brown resin by repeated decan- tations, allows to crystallise and purifies by recrystallising.—Forms pale-yellow, shining silky tufts of almost tasteless ciystals; loses its water at 100°; does not fuse at 130°; dissolves readily in cold and in hot water, and in alcohol, not in ether; colours black the solutions of iron; decomposes with diluted acids into sugar aiul Rhamnetin = C22 Hio Oio, forms with alkalies brown solutions. XailtllOtauilic Aci(l=:Ci8 His O4. The yellow matter of autumnal leaves. Exhaust, for instance, elm-leaves with alcohol, evaporate the tinctures, filter off the wax, precipitate the filtrate with watei-, filter again, precipitate with acetate of lead and decompose the deposit by sulphuret of hydrogen. The liquid separated from the sulphide of lead, has an astringent taste, acid reaction and precipitates glue. \ailthoxyleil=:C2o Hie. Obt^iined by distilling the so-cal]o<l Japanese pepper (seeds of Xanthoxylum piperitum) with water, desiccating the oil with chloride of calcium and rectifying by means of potassium. Colourless, of great light-refracting power, and of a pleasant aromatic odour; boils at 162°. Q 2$