227 



hai-d at — 27°, dries better at the air tlian linseed oil, yields like 

 this soft soaps. 



\illltlliu, 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 with ammonia and digested with a little 

 hydrated alumina, which deposit alizarin and rubiacin, yield the 

 Xanthin 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, gummoiis body, bitter (neither acerb nor sweet), fuses and 

 decomposes in higher temperatures, dissolves readily in water Avitli 

 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, 



Xailthoi'lia milium 0*46 H2SO28 + 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 chrysoi-hamnin of the unripe beriies. After boiling 

 the unripe berries \vith water for a few minutes and diying, no 

 chrysorhamnin is obtained, but in its stead Xanthorhamnin. Like- 

 wise Xanthorhamnin is obtained from chrysoi'hamnin by l)oiling the 

 latter with water under access of air. Gellatly boils the unripe pul- 

 verised berries with alcohol, frees the not too much concentrated 

 tinctiu'e 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 crystals; loses its 

 water at 100°; does not fuse at 130"; dissolves readily in cold and 

 in hot water, and in alcohol, not in ether; coloiirs black the 

 solutions of iron; decomposes with diluted acids into sugar and 

 Rhamnetin = Coo Hio Oio, forms with alkalies brown sohitions. 



XailtllOtailllic 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 water, filter again, precijHtate with acetate of lead and 

 decompose the deposit by sulphuret of hydrogen. The liquid 

 separated from the siilphide of lead, has an astringent taste, acid 

 reaction and precipitates glue. 



-\ailthoxyleil=:C2o Hie. Obtained by distilling the so-called 

 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 



