322 MISSOURI AGR. EXP. STA. RESEARCH BULLETIN No. 9. 



Among the seeds, Schunck 1 has found the annatto pigment to be a 

 carotin. 



The Xanthophylls. 



It was mentioned above that it has been found that a second class 

 of pigments usually accompanies carotin. Investigations of this class 

 of pigments, now called xanthophylls, has not been as extended as 

 that of carotin but the constitution and properties of the xanthophylls 

 are nevertheless at present established. 



Sorby 2 differentiated the pigments accompanying chlorophyll as 

 xanthophyll, orange xanthophyll, and yellow xanthophyll, all with 

 spectroscopic properties. J. Borodin 3 observed that besides carotin, 

 a second crystallizable yellow substance exists in leaves which is much 

 more soluble in alcohol than carotin and insoluble in benzine. Im- 

 mendorff 4 denied the existence of more than one pigment as was 

 noted above. Monteverde 5 confirmed Borodin's observations. 

 Tschirch 6 in 1896, showed that green leaves contain a second yellow 

 pigment which, however, showed no absorption bands. Tschirch called 

 the second pigment xanthophyll. The name, however, was a misnomer, 

 for Schunck 7 later showed that Tschirch was dealing with a group of 

 water and alcohol soluble pigments probably identical with the lich- 

 noxanthine described by Sorby. 8 Tschirch 9 later recognized the ex- 

 istence of a true second yellow crystallizable pigment. 



Molisch 10 in his critical study of the yellow pigments left the 

 question of their plurality an open one, and Tammes n also left the 

 question undecided. 



Schunck 12 in his widely known spectroscopic study of the yellow 

 pigments of plants and flowers, demonstrated beyond a doubt that a 

 second great group of pigments, which he designates the xanthophylls, 

 accompanies the crysophyll. He differentiated three different xantho- 

 phylls and designated them L. B. and Y. xanthophyll, respectively. 



He found that the xanthophylls were all characterized by giving 

 the same color reactions in the dry state as crysophyll and three 



1. Proc. Roy. Soc. 72, 1903. 



2. Proc. Roy. Soc. 21, p. 457 (1875). 



3. Melanges Biol. tir. d. bull d. L'Acad. Imp. d. St. Petersb. 11, p. 512 ( 1883 ) . 



4. Loc. cit. 



5. Loc. cit. p. 148 (1903). 



6. Ber. d. d. Botan. Gessel, 14, p. 76 (1896). 



7. Proc. Roy. Soc. 72 (1903). 



8. Loc. cit. 



. Ber. d. d. Botan. Gessel. 22, p. 414 (1904). 



10. "Die Krystallization und der Nachweis des Xanthophylls (carotins) 

 in Blatte" (Ber. d. Deut. Botan. Ges. 14, p. 18 (1896). 



11. Loc. cit. (1900). 



12. Proc. Roy. Soc. 65 (1899); 68 (1901); 72 (1903.) 



