CAROTIN, THE PRINCIPAL YELLOW PIGMENT OF MILK FAT 403 



The corpora lutea were carefully cut away from the surround- 

 ing tissue, ground up with sand, and extracted with ether. In this 

 solvent and in alcohol, the pigment showed two absorption bands 

 in the blue part of the spectrum. Solubility tests on the alcohol 

 solution showed that petroleum ether and carbon bisulphide ex- 

 tracted almost all the pigment. That which was not extracted was 

 treated with hot alcoholic potash and the soap extracted with ether in 

 which the pigment all readily went. The saponified pigment was trans- 

 ferred to alcohol and freed from cholesterol with digitonin. After 

 concentrating, the cholesterol-free filtrate was extracted with carbon 

 bisulphide. Not all the pigment was extracted even with two ex- 

 tractions, and petroleum ether extracted no color from the remain- 

 ing light-yellow alcoholic solution. The experiments with the sec- 

 ondary pigment were not carried farther at this time as the signifi- 

 cance of its presence was not appreciated, but viewing the data in 

 the light of the results of the milk fat and body fat investigations 

 it is evident that a secondary xanthophyll pigment was present here. 

 This has been emphasized because the results of the investigations 

 subsequently conducted were unfortunately vitiated because of un- 

 expected aldehyde resin colorations which developed during saponi- 

 fication. It was shown by a special study that these reddish yellow 

 bodies when present in considerable quantity are extracted from 

 the diluted alkaline solutions by ether, but are not readily extracted 

 from alcohol by petroleum ether. Consequently they interfere with 

 a proper study of the pure pigments. Such a result was obtained 

 in the study of the corpora lutea pigments of Cow No. 8 and the 

 Hereford cow. The only noteworthy result of that investigation was 

 to obtain a beautiful rose colored unadsorbed zone in a chromoto- 

 gramm of a carbon bisulphide solution of the combined pigment. 

 This solution showed three absorption bands, the measurements of 

 which are given in Table 5. 



The next investigation was with the corpora lutea of Hoi stein 

 Cow No. 207. As stated above there was no well-developed corpus 

 luteum, the largest part of the pigment obtained being from the re- 

 mains of several former corpora lutea which were present as small 

 red colored patches about the size of a pin head. These were care- 

 fully cut out and macerated with a little sand and CaSO 4 and extracted 

 with carbon bisulphide for several hours. The solution, of about 

 25-50 c. c. volume, had a deep orange-red color, which showed" three 

 beautiful bands, the third band being considerably fainter than the 

 first two. The measurements are given in Table 5. 



