244 PIGMENTS 



to form a compound C 40 H 54 O 6 I 4 . Unlike carotin and xantho- 

 phyll, which are neutral substances, fucoxanthin has basic pro- 

 perties, and forms blue salts with hydrochloric and sulphuric 

 acids. 



FURTHER LITERATURE. 



General. 



Hansen : " Die Farbstoffe des Chlorophylls," Darmstadt, 1889. 



Krauss : " Zur Kenntniss der Chlorophyllfarbstoffe," Stuttgart, 1872. 



Liebaldt: "Zeitsch. Bot.," 1913, 5, 65. 



Schryver : " Science Progress," 1909, 3, 425. 



Stahl: "Zur Biologic des Chlorophylls," Jena, 1909. 



Tschirsch : " Unters. ii. Chlorophyll," Berlin, 1884. 



Annual Reports of the Chemical Society of London, 1910, 1911, 1912, 1913, 



1914, 1915. 



Willstatter and Stoll : " Unters. ii. Chlorophyll," Berlin, 1913. 

 Willstatter: " Ber. deut. chem. Gesells.," 1914, 47, 2831; "J. Amer. Chem. 



Soc.," 1915, 37, 323. 



On the Constitution of the Blood Pigment and its Relation to Chlorophyll, 

 Nencki and Zaleski : " Ber. deut. chem. Gesells.," 1901, 34, 997. 

 Piloty: id., 1910, 43, 489; " Annalen," 1910, 377, 314. 

 Willstatter and Fischer: "Zeit. physiol. Chem.," 1913, 87, 423. 

 Knorr and Hess : " Ber. deut. chem. Gesells.," 1911, 44, 2758. 

 Kiister : " Annalen," 1906, 345, i ; " Zeit. physiol. Chem.," 1913, 88, 377. 



ANTHOXANTHINS. 

 FLAVONES AND XANTHONES. 



Under the headings of Flavones and Xanthones (two words 

 derived from the Latin and Greek for yellow) are included a 

 number of yellow pigments occurring in the vegetative organs 

 and in the petals of many plants. Owing to their close re- 

 lationship to the blue colouring matters known as Antho- 

 cyanins, Willstatter and Everest,* have proposed the adoption 

 for them of the generic te-m, Anthoxanthin, at first suggested 

 by Marquart in 1835. These yellow pigments are often of con- 

 siderable economic value as dye-stuffs. They occur naturally 

 in combination with rhamnose or glucose as glucosides and in 

 some cases uncombined, and frequently are also associated 

 with tannins. 



The mother substances from which all these substances 

 are derived and from which they derive their name are the 

 two compounds Flavone and Xanthone. 



* Willstatter and Everest: " Annalen," 1913, 401, 189. 



