430 ORIGIN OF MILK FAT 



casein in the milk. According to E. Liesegang the addition 

 of the ether, by precipitating the casein emulsion, produces 

 the formation of the membrane as an artefact. When potash 

 solution is added the ether does not meet an emulsion of 

 casein, but a solution of casein, and therefore cannot induce 

 membrane formation. It has been long known that the fat 

 of human milk, in contrast to that of cow's milk, is directly 

 soluble in ether; this, according to Kreidl and Lenk, 85 de- 

 pends on the fact that casein is not present in human milk in 

 the form of ultramicroseopically demonstrable particles, but 

 in solution. 



85 A. Kreidl and E. Lenk (Verhandl. d. morpholog-physiol. Ges., Wien), 

 Centralbl. f. Physiol., 25, No. 12, 1911. 



