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 H 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. 



Hsematoxylin, 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 



