CAROTIN, THE PRINCIPAL YELLOW PIGMENT OF MILK FAT 425 



TABLE No. 4. RELATION BETWEEN CHARACTER OF RATION AND AMOUNT OF 

 PIGMENT IN MILK FAT AND BLOOD SERUM. 



The results of this experiment are as striking and conclusive 

 as in the experiment with Cow No. 301, and show that there is a 

 direct relation between the amount of carotin in the food and the 

 amount of lutein in the blood serum, just as there is a direct relation 

 between the presence of an excess of carotin in the food and the 

 production of a high-colored butter fat. It is necessarily true also 

 that there is a direct relation between the color of the butter fat 

 and the amount of lutein in the blood serum. A small amount of 

 lutein in the blood serum will always mean a light-colored butter fat. 

 It does not appear to be necessarily true, however, that a high-colored 

 serum will be accompanied by a high-colored butter fat. The only 

 conclusion in this connection that can be drawn from the data of Tables 

 3 and 4 is that an increase in the color of the blood is accompanied by 

 an increase in the color of the fat. The actual color of the fat under 

 these conditions is apparently dependent upon a number of conditions 

 which are not explained by this data. The amount of fat being 

 produced and the breed of the animal are both factors which probably 

 influence the color of the fat. There is certainly a wider difference 



