CAROTIN, THE PRINCIPAL YELLOW PIGMENT OF MILK FAT 347 



adsorbed pigment at the bottom of the differentiation having a rose 

 color. The stream of carbon bisulphide was continued until the rose 

 colored solution began to drop from the lower end of the tube. The 

 appearance of the column at this time is shown in Figure II. The 

 stream of carbon bisulphide was now continued until the rose colored 

 zone had entirely passed through. 



According to Tswett this zone contained only carotin. The beau- 

 tiful rose or red orange solution that was obtained was studied as 

 follows : It was first examined in the spectroscope where it showed two 

 distinct bands, and a faint third one. (See Table i.) The carbon bisul- 

 phide solution was then evaporated. The 

 residue was on orange yellow solid. A 

 portion of it gave a beautiful blue colora- 

 tion with concentrated H 2 SO 4 . 



The remainder of the residue was 

 dissolved in hot ninety-five per cent alco- 

 hol, and the phystosterol which precipi- 

 tated out on cooling filtered off. The fil- 

 trate was divided into two portions, pe- 

 troleum ether (b. p. 30-50 C) being 

 added to one and pure carbon bisulphide 

 to the other. On separation of the re- 

 spective solvents with a little water, the 

 pigment was found quantitatively in the 

 petroleum ether and carbon bisulphide 

 layers respectively. The pigment was 

 again put into alcohol, and in this solv- 

 ent showed two strong absorption bands 

 and end absorption. (See Table i.) 



Potassium hydroxide was now added 

 to the alcoholic solution and the solution 

 boiled for several hours. The alkaline 

 solution was diluted with three volumes 

 of distilled water and extracted with an 

 equal volume of ether. The ether com- 

 pletely and readily extracted the pigment, FIGURE II. 

 showing it to be unsaponifiable. The golden yellow ether solution was 

 washed free from alkali with water and evaporated to dryness. The 

 residue was taken up with alcohol. This solution showed only two 

 bands. (See Table i.) 



The alcoholic solution was now tested again for its relative 

 solubility toward petroleum ether (b. p. 30-50 C) and carbon bisul- 



3 



Colorless. 



Zone I: Yellow. 



Colorless. 



/ Zone II: 

 I Yellow. 



Colorless. 



Green Zone. 



/Zone III: 



\ Yellow. 

 Colorless. 



/ Zone IV: 



\ Orange- Yellow. 



f Greenish- 



1 Brown Zone. 



Zone V: Rose. 



Cotton Ping. 



