4l8 MISSOURI AGRICULTURAL EXP. STA. RESEARCH BULLETIN NO. 12 



tatively extracted the yellow pigment from its alcoholic solution on 

 dilution with a little water. This result at once indicated the carotin 

 nature of the blood serum lutein, and this was confirmed by the experi- 

 ments reported below. 



The methods used for isolating the pigment in these studies varied 

 somewhat in detail but were all based upon a preliminary, more or 

 less complete dessication of the blood serum by calcium sulphate 

 (plaster of Paris). The details are given in connection with the report 

 of the experiments. 



CHEMICAL IDENTIFICATION OF THE PIGMENT. 



The following experiments were conducted to show the chemical 

 relation of the blood serum lutein to the carotin and xanthophylls. 



Experiment I. 



About 20 cubic centimeters of golden yellow serum from Jersey 

 Cow No. 8* was mixed with plaster of Paris until almost dry, dried 

 for a few minutes on the steam bath, the mass pulverized, and shaken 

 with successive volumes of petroleum either in an Erlenmeyer flask 

 until no more color appeared in the petroleum ether. The extract was 

 light yellow in color and no color was extracted from the concentrated 

 solution by 80 per cent alcohol. The plaster of Paris mass was now 

 shaken with successive proportions of petroleum ether containing 10 per 

 cent absolute alcohol, until the extraction was colorless. The resulting 

 extract had a deep yellow color containing many times as much pigment 

 as the extract with petroleum ether alone. This solution, after con- 

 centration, was extracted with 80 per cent alcohol. Apparently no 

 color was extracted. The petroleum ether solutions were combined, 

 evaporated to dryness and the residue dissolved at once in carbon 

 bisulphide giving a deep red-orange solution which showed 3 absorp- 

 tion bands, Band III being much fainter than the other two. The 

 measurements of the bands are given in Table No. 2. 



Experiment II. 



Fifty cubic centimeters of the same serum was completely dessi- 

 cated with plaster of Paris and the pulverized mass shaken with absolute 

 alcohol and ether until no more color was extracted. The ether was 

 distilled off and the golden-yellow alcoholic solution saponified with 



*Note: The serum in this case and in all subsequent cases was obtained 

 by allowing the freshly drawn blood to clot in a tall cylinder or jar and 

 the serum which pressed out on standing syphoned off into glass stoppered 

 bottles. 



