70 CAROTINOIDS AND RELATED PIGMENTS 



whether the crystals were carotin or xanthophylls. Schunck's com- 

 bined separation and photospectrographic procedure, together with the 

 effect of certain reagents on the absorption bands, has already been 

 described in detail. Schunck reported especially the distribution of 

 his L. B. and Y. xanthophylls, respectively, in a number of common 

 yellow flowers. The author is of the opinion that Schunck's work can 

 be relied on merely as having shown that xanthophyll carotinoids are 

 present in the particular flowers examined by him. The author re- 

 cently 9 sought to verify Schunck's observation that the pigment of 

 the common dandelion (Taraxacum officinale) is compared solely of 

 B. xanthophyll, which corresponds with Tswett's a' and a" xantho- 

 phylls, with the view of determining the influence of a single xantho- 

 phyll on the coloration of egg yolk when fed to laying hens. Only the 

 purest yellow parts of the dandelion head were examined. Applying 

 relative solubility, spectroscopic and chromatographic adsorption 

 methods to the extracted pigment, it was found, however, that carotin 

 and at least three xanthophylls were present, carotin being especially 

 abundant. Xanthophyll (5 (Schunck's Y. xanthophyll), characterized 

 by the peacock-blue color of its alcoholic solution on treatment with 

 HC1, was among the xanthophylls present. 



Tschirch used a still different method for his flower studies. The 

 alcoholic extracts were submitted to the capillary analysis procedure 

 first introduced by Goppelsroeder (1901), and the carotinoid char- 

 acter of the principal yellow zone confirmed spectroscopically. 



This capillary method of separation has not been mentioned pre- 

 viously so that a few statements concerning its character may be made 

 at this point. The alcoholic extract of the flower whose pigments are 

 to be examined is placed in a cylindrical vessel with a flat bottom and 

 strips of thick, fat-free paper, such as that used for the Adams' milk- 

 fat analysis, are immersed in the solution to a depth of about one 

 centimeter. The strips used by Tschirch were 5 cm. wide, 18 cm. long 

 and about 1 mm. thick. These strips are hung from a support. Dur- 

 ing the course of several hours the pigmented extract gradually rises 

 on the paper and as it does so differentiates itself into colored zones, 

 strikingly similar in appearance to those obtained in the Tswett 

 chromatographic analysis. When the capillary rise has ceased the 

 paper strips are removed, dried, and the various colored zones sepa- 

 rated with the scissors. The pigment in the individual zones is puri- 

 fied by repeating the capillarity until the paper takes up only one 



Unpublished investigation. 



