178 



EXPERIMENT STATION RECORD. 



Reactions of albuminoids — Continued. 



Boiling with strong sulphuric acid. 



Solubility. 



Color of solution. 



Boiling with 

 weak soda 



solution. 



Solubility. 



Serum globulin (horses' blood) 

 Serum albumen (horses' blood). 



Easily soln- 

 ble. 



do 



Dark red-brown, green fluorescence 

 Dark-brown, slightly fluorescent 



Fibrin (swine blood) do do 



Egg albumen do ' Brown (faintly reddish). 



Lactalbumen (cows' milk) do Light brown 



Casein (cow s' milk) do Light brownish-yellow, strongly fluo- 

 rescent. 



Albuminoid of tat globules (cows' do Dark reddish brown 



milk). 



Difficultly 



soluble. 



Easily solu- 

 ble'. 

 Do. 

 Do. 



Difficultly 

 soluble. 



Very easily 

 soluble. 



Very diffi- 

 cultly solu- 

 ble. ' 



The nitrogen content of the albuminoid of the fat globules was found 

 to lie between 14.20 and 14.79 per cent. The following data are giveu 

 for other albuminoids: Serum globulin, 15.85 per cent; serum albumen, 

 16.04 per cent; fibrin, 10.91 per cent; egg albumen, 15.25 per cent; 

 casein, 15.70 per cent; lact albumen, 15.77 per cent. Heated for a time 

 with dilute hydrochloric acid, a substance is formed in case of the 

 albuminoid of the fat globules which reduces copper oxid in alkaline 

 solutions, viz, about 6.5 (6.24-6.88) parts of reduced copper per 100 parts 

 of ash-free substance. This reaction is not given by albumen or casein., 

 but by serum globulin (Morner), the glycoproteids, and several muscle 

 proteids (Hammersten;. 1 



The author believes this albuminoid firmly adheres to the fat globules 

 as a membranous covering. He rejects Danilewsky and Radenhauseirs 

 theory 2 of an albuminous stroma of the globules. He succeeded in col- 

 oring the membrane by the following method of procedure : About 50 cc. 

 of washed cream was mixed with 200 cc. of a highly colored solution, 

 picrocarmin or nigrosin giving particularly satisfactory results. The 

 mixture was left to cream in a tall cylindrical separatory funnel; after 

 24 hours a fairly thick layer of cream had usually separated out, and 

 this was of a lighter color than the staining solution used. The lower 

 liquid containing the small fat globules was placed in another separa- 

 tory funnel, and left to cream once more. The cream was diluted with 

 4 times its volume of a 10 per cent sugar solution, mixed, and left to 

 rise, after which the colored solution was drawn off from below and the 

 cream washed with new sugar solutions until this did not show any 

 color on being mixed with the cream and left standing. The cream 

 thus obtained had, in case picrocarmin solution was used, a pink color, 

 and could be mixed with water without imparting any color to the 

 water. No color could be distinguished under the microscope. When 

 shaken with alcohol and ether, the fat was dissolved from the cream 

 thus prepared, and the albuminoid thrown down as a highly red colored 

 precipitate. 



The cream obtained from the portion containing the small fat globules 



Lehrb. physiol. Ch'em., 1895. 



Forsch. Geb. Viehkaltung, 1880, No. 9. 





