CAROTIN, THE PRINCIPAL YELLOW PIGMENT OF MILK FAT 361 



nature of the pigments of various common cattle foods before con- 

 ducting any feeding experiments to prove that there is a direct rela- 

 tion between the presence of carotin in the butter fat and the presence 

 of carotin in the food. It was at first merely sought to show the 

 presence or absence of unsaponifiable yellow pigments in various 

 foods, by extracting them with hot alcohol, saponifying the extract 

 with potassium hydroxide and extracting the pigment from the soap 

 with ether. From this standpoint, it was found that among the 

 grains and concentrates, wheat bran, linseed meal, dried brewer's grains 

 and cottonseed meal all showed the presence of small amounts of un- 

 saponifiable yellow pigments, while white corn was found to be the only 

 common grain absolutely free from such pigments. Yellow corn was 

 of course found to be rich in unsaponifiable yellow pigments. Some 

 roughages such as corn silage and cottonseed hulls were found to 

 contain small amounts of unsaponifiable pigments, while wheat straw 

 and oat straw were practically free from them. The hays were 

 found to be the most variable of all feeds. All green hays, 1 such 

 as alfalfa, first-class clover and the very best timothy were found 

 to contain considerable amounts of unsaponifiable yellow pigments, 

 the amounts varying with the greenness of the hay. Bleached hays, 

 whether timothy, clover, or alfalfa were more or less free from un- 

 saponifiable yellow pigments. 



Some feeds were investigated more particularly with a purpose 

 of showing the character of the unsaponifiable yellow pigments. With- 

 out reporting the experimental details in all cases, but merely stat- 

 ing that the methods of analysis were spectroscopic, chromotographic, 

 and solubility methods, the following results were obtained. 



Cotton Seed Meal and Cotton Seed Hulls. It was found that the 

 unsaponifiable yellow pigments of cottonseed meal and cottonseed 

 hulls were due entirely to the oil they contain; and further that this 

 oil which is known to be characterized by its yellow color contains 

 equal proportions of carotin and xanthophyll. The carotin is the 

 usual one met in other places, while the xanthophyll is made up of 

 at least five different constituents according to their adsorption prop- 

 erties. The chief xanthophyll is not adsorbed to any extent by CaCO 3 

 from its carbon bisulphide solution, and in this solvent shows absorption 

 bands of characteristic position, shifted considerably toward the blue 

 from the normal xanthophyll bands. In CS 2 the bands measured: 

 I, 238-260; II, 285-303; III, 355. The remainder of the xanthophylls 

 were so firmly held by the CaCO 3 that they could not be readily 



1. By green^ hay is meant hay that has been cured under such conditions 

 that it still retains a large part of the green color which characterizes its uncut 

 condition. The green alfalfa hay referred to throughout this paper was west- 

 ern cured alfalfa which had a remarkably bright green color. 



