CAROTIN THE PRINCIPAL NATURAL YELLOW PIGMENT 

 OF MILK FAT Part IV, * 



A. The Yellow Pigment of Blood Serum. 



B. Carotin and Xanthophylls During Digestion. 



C. The Pigments of Human Milk Fat. 



LEROY S. PALMER and C. H. ECKLES. 



A. THE YELLOW PIGMENT OF BLOOD SERUM 



Very few investigations have dealt with the so-called lutein of the 

 blood serum. Thudichum 1 was the first to mention it and classify 

 it as a lutein. Schunck, 2 a number of years later, showed that the 

 lutein of fowl serum was spectroscopically identical with the L. 

 xanthophyll which he isolated from yellow flowers and green plants. 

 Halliburton 3 also studied the lutein of the serum of the hen, but the 

 pigment isolated by him had evidently lost its spectroscopic properties 

 in view of Schunck's investigation. Finally, Krukenberg 4 extracted 

 the lutein from ox serum by shaking with amyl alcohol. The extract 

 showed two absorption bands. He used the designation lipochrome 

 for the pigment. His work is usually mentioned in the present text 

 books of physiological chemistry. 



Recent investigations in connection with various animal luteins 

 or lipochromes have shown that they may be classified as belonging 

 to the widely distributed carotin or xanthophyll groups of pigments 

 of the vegetable world. Willstatter and Escher 5 have identified the 

 pigment of egg yolk as an isomer of the crystalline xanthophyll of 

 green plants ; and Escher 6 has shown that the principal corpus luteuni 

 pigment is identical with the carotin of plants. Extending this work 



*See Research Bulletin No. 9, p. 312, for statement of Co-operation with 

 TJ. S. Dept. of Agriculture. 



1. Proc. Roy. Soc. 17, p. 253 (1869). 



2. Proc. Roy. Soc. 72, p. 165 (1903). 



3. Jour. Physiol. 7, p. 324 (1886). 



4. Sitz, Ber. d. Jen. Gessel. (1885). 



5. Zeit. f. Physiol. Chem. 76, pp. 214-225 (1912). 



6. Zeit f. Physiol. Chem. 83, p. 198 (1913). 



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