35O MISSOURI AGRICULTURAL EXP. STA V RESEARCH BULLETIN NO. IO 



These tests showed conclusively that this pigment belongs to the 

 oc group of xanthophylls ; and that its adsorption, solubility and 

 spectroscopic properties which are characteristically different from 

 those of carotin, are unaltered by treatment with alcoholic potash. 



The remaining xanthophyll pigment was so firmly held in com- 

 bination with the CaCO 3 that carbon bisulphide would not wash it 

 out. A stream of ten per cent alcoholic petroleum ether was there- 

 fore run through the column, washing out all the remaining pigments. 

 The resulting solution showed only faint absorption bands, indicat- 

 ing that the pigments noted above, i. e. carotin and xanthophyll oc, 

 are the principal yellow pigments of the alfalfa hay. 



IDENTIFICATION OF THE PIGMENT OF BUTTER FAT. 



With the properties of carotin and xanthophylls well established, 

 attention was next directed to the butter fat pigment. The follow- 

 ing experiments were carried out, the results of which are very 

 striking. 



Experiment i. 



Fifteen grams of very yellow butter fat from a Jersey cow who 

 was on fresh, green, fall grass was saponified in the usual way with 

 alcoholic potash, taking great care to avoid the presence or formation 

 of the colored alcohol decomposition products, the aldehyde resins. 

 After dilution the soap was extracted with ether. The ethereal extract 

 was washed free from alkali with distilled water and evaporated into 

 ninety-five per cent alcohol. An equal volume (100 c. c.) of petroleum 

 ether (b. p. 30-50 C.) was now added to the alcoholic solution and 

 just enough water to cause a separation of the alcohol and petroleum 

 ether. The golden yellow petroleum ether layer which resulted, con- 

 tained practically all the color. The alcohol layer was drawn off 

 and extracted with fresh volumes of petroleum ether until only a 

 trace of color went into the petroleum ether layer. All the petroleum 

 ether extracts were then combined and extracted with eighty per 

 cent alcohol. A mere trace of color went into the alcohol. The 

 alcohol solutions were combined. 



The Petroleum ether solution This contained by far the greatest 

 part of the total pigment. The solution was evaporated quickly at 

 a temperature below 50 C., leaving a red oily residue which instantly 

 dissolved in carbon bisulphide with a deep red orange color. After 

 adjusting the concentration for the 10 m. m. cell, so that the bands 



