458 H^EMATOXYLIN. 



acid, forming a green liquid, from which it can be 

 thrown down with boiling water. It is also soluble in 

 alcohol and ether. 



Columbin, C 21 H 22 7 , in columbo-root (of Cocculus 

 palmatus), together with berberine and a pale-yellow, 

 almost insoluble substance, columbic acid. Colorless 

 prisms, having a bitter taste. 



Curcumin, C 10 H 10 3 . The coloring matter of tur 

 meric root. Can be most readily extracted by means 

 of boiling benzene, in which but little of the remain 

 ing constituents of the root is soluble. Orange-yel 

 low prisms, of a weak, vanilla-like odor ; fusing point, 

 165 ; almost insoluble in water, difficultly soluble in 

 carbon bisulphide and benzene at the boiling tempera 

 ture, easily soluble in ether and alcohol ; soluble in 

 alkalies and alkaline carbonates, the solutions having 

 a brownish-red color. Acids precipitate the curcumin 

 from the solutions in the form of yellow powder. 

 Paper colored with curcumin turns a brownish-red 

 when brought in contact with liquids that have an 

 alkaline reaction; on drying, this color changes to 

 violet ; acids restore the original yellow color ; when 

 moistened with a solution of borax, and then- dried, it 

 turns orange-yellow, and this color is not changed by 

 dilute acids, but is converted into blue by alkalies. 



Gentianin (Gentianic acid), C 14 II 10 5 , in the root of 

 Gentiana lutea, which owes its bitter taste, however, 

 not to this, but to another, uninvestigated substance. 

 Fine, bright-yellow prisms, without taste; scarcely 

 soluble in water, soluble in alcohol; partially subli m- 

 able ; soluble in alkalies, forming bright-yellow solu 

 tions. Yields, with alkalies, salts which crystallize 

 well, and are decomposed even by carbonic acid. 



Haematoxylin, C 16 H 14 6 , in logwood (Hcematoxylin 

 campechianum), from which it can be extracted with 

 water or, better, ether. Yellow, transparent prisms, 

 which, when heated, give up water of crystallization. 

 It possesses a sweetish taste, and is sparingly soluble in 



