MICROCHEMISTRY. IO/ 



c. Other Coloring 1 Matters dissolved in Fats or Ethereal Oils. 



182. Of the other pigments which from their chemical 

 reactions do not belong to the lipochromes, but occur dis- 

 solved in fats or ethereal oils in the living plant, only curcu- 

 min has been microchemically investigated. 



Curcumin, Ci 4 H 44 O4. 



Curcumin occurs, according to O. Herrmann's investiga- 

 tions (I, 24), in the fresh rhizome of Curcuma aniata within 

 the parenchymatous cells of the fundamental tissue, dis- 

 solved in an ethereal oil. This author uses, for its micro- 

 chemical recognition, lead acetate, which forms a brick-red 

 precipitate with the curcumin, and sulphuric acid, which 

 colors it crimson. 



d. Coloring Matters dissolved in the Cell-sap. 



183. The pigments dissolved in the cell-sap have been 

 little studied. There are usually distinguished only two 

 different pigments or groups of closely-related compounds : 

 namely, anthocyanin or cyanin, and anthochlorin or xanthe'm. 

 The first of these produces red, blue, or blue-green colors^ 

 and the latter the yellow and yellow-brown tones. 



a. Anthocyanin. 



184. Anthocyanin is readily soluble in water, and has i'rr 

 this solution, according as its reaction is more or less acid 

 or alkaline, a red, violet, blue, blue-green, green, or yellow- 

 green color. It is wholly decolorized by strong alkalies. It 

 is also soluble in alcohol and ether. 



Whether all the pigments called anthocyanin are chemi- 

 cally identical must be determined by future studies. Han- 

 sen (III) believes in the identity of the red and blue pig- 

 ments prepared from various organs, on the ground of his 

 spectroscopic investigations. 



But N. J. C. Miiller (I) has recently endeavored to show 

 that a considerable number of very different compounds 

 have heretofore been called anthocyanin. But, as> this. 



