VEGETABLE PRODUCTS. 157 



and alcohol. The coloring matter of the yellow series is rather 

 resinous, and is colored blue by sulphuric acid. They are un- 

 doubtedly modifications of chlorophyl. 



Alizarin and Purpurin, C 20 , H 10 , O 10 , are the coloring matter 

 of Madder, from the root of the Kubia tinctoria. Alizarin is 

 soluble in boiling water. Takes various colors in varied cir- 

 cumstances, but is used in dyeing red. The Turkey- red pro- 

 duced on cotton is produced by alizarin. With alumina it 

 forms Madder-lake. Animals with madder taken in their food 

 have their bones colored red. 



Anchusin, a red, resinous coloring matter, is from the An- 

 chusa tinctoria. It assumes a great variety of colors, under 

 different circumstances. 



Carthamin, from the Carthamus tinctorius. A red and yellow 

 coloring matter is obtained from it. 



Hematoxylin is the coloring matter of Logwood. The ex- 

 tract by ether is yellow. Ammonia changes it to a dark red ; 

 Potassa, to a violet ; Hydrates of the earths, oxides of zinc, and 

 Bismuth, to purple ; Iron, to black. 



Cucurmin, turmeric, is from the root of the Cucurma longa ; 

 Dragon's-blood, from the Dracaena draco. Various lichens give 

 peculiar coloring matters, from one of which our Litmus comes. 



Whence alizarin and purpurin? Anchusin? Carthamin ? Haematoxv- 

 lin? Turmeric? Dragon's-blood? Litmus? 



