54 



ein with tannic acid. Collect and wasli the deposit and mix 

 intimately in the moist state with oxyd of lead, dry the mixture 

 by heat and exliaust with hot alcohol, evaporate the tinctui-e to a 

 syi'vip-like consistence and allow to dry over sulphuric acid in the 

 vacuum. To get it completely pure, it must be thrown down re- 

 ])eatedly ■svith tannic acid and treated with oxyd of lead as above. — 

 Light-yellow, brittle, adhering like a resin when triturated, of a 

 faintly aromatic hay-like odour; dissolves readily in water and 

 alcohol, not in ether, has even in a very diluted solution a strong 

 and lastingly bitter taste, is of neuti-al reaction, fuses at 140° and 

 is decomposed by higher temperatures, yields an intensely yellow 

 precipitate with mineral acids and alkalies, is thrown down by 

 tannic acid, the chlorides of mercury and of gold; dissolves in 

 concentrated sulphuric acid with dark-green colour which changes 

 soon into yellow and is altered by nitric acid successively into 

 blue, violet, and brown, and lastly yellow again, which becomes 

 of a dark-red colour with ammonia. The Colchicin possesses no 

 basic px'operties, and is even changed into a weak acid when 

 treated with a mineral acid, and assumes thereby a crystalline 

 appearance, but loithout altering its comjiosition. This slightly 

 acid compound has been called Colchicein; it forms white warty 

 masses and needles, tastes much less bitter than Colchicin, and 

 is of a slightly acid reaction, but possesses the same poisonous 

 properties as the latter. 



ColOCyntIlill=:C56 H42 O23. In the pulp of the fruit, less in 

 the seeds, of Cucumis Colocynthis. Treat the aqueous extract after 

 drying with cold water, precipitate the filtered liquid with acetate 

 of lead, filter again and preci})itate with sub-acetate of lead, strain 

 and remove the excess of lead by sulphuret of hydrogen, precipi- 

 tate with tannic acid, collect and wash the deposit, mix it with 

 hydrated oxyd of lead, warm and exhaust with alcohol, decolourise 

 the tincture with animal charcoal, filter, dry and shake with ether 

 (anhydrous) which leaves the C. in the pui-e state. — Amorphous, 

 yellow, crystallises in white-yellow tufts when the alcoholic solu- 

 tion is slowly evaporated, has an intensely bitter taste, burns when 

 heated, dissolves in 8 parts cold and in 6 parts boiling water, in 6 

 parts aqueous and in 10 parts absolute alcohol, not in ether, in 

 concentrated sulphuric acid with crimson-red colour ; secedes with 

 diluted acids into sugar and another product. 



ColOIIlbic Aci(l=C42 H22 O12 + HO. Besides colombin and 

 berberin in the Colombo-root (from Jateorrhiza palmata). 

 Digest hot the dried alcoholic extract of the root with milk of 

 lime, saturate the filtered liquid with hydrochloric acid, which 

 causes a yellow amorphous precipitate, remove from the latter the 

 l:)erberin by washing with water, and the colombin by boiling 

 with ether, dissolve the rest in ley of jiotash and adduce carbonic 



