320 THE MILK OF MAMMALS OTHER THAN THE COW. 



TABLE LXXIX. 



. In 15 cases the fat was higher before suckling than after 

 suckling, and in 21 it was lower, while in 1 case it was identical. 

 The cases in which the fat was higher before suckling than after 

 wer generally when the mother was lying down, indicating that 

 the separation of cream was largely mechanical. 



Comparision with Cow's Milk. The following differences in 

 composition of the various constituents from that of the cow 

 have been noticed : 



Fat. This is very low in volatile acids (see p. 315). It 

 appears to contain free fatty acids ; Leeds noted that many of 

 the fats extracted from the copper-protein precipitate obtained 

 by Ritthausen's process were tinted green ; Carter and the 

 author confirmed this, and found the following percentages of 

 copper oxide (CuO) in the fats thus extracted : 



2-80 



1-27 



0-87 



0-62 



0-30 



The copper could be removed easily by shaking with dilute 

 hydrochloric acid, and the fat behaved to copper salts in every 

 way as if it contained free fatty acids. 



Carter and the author found the refractive index at 35 C. to 

 vary from 58 -4 (in a milk which upset the child, which finally 

 died in convulsions) to 48-2 (in a milk on which the child throve 

 remarkably well). The analyses of these two samples were : 



TABLE LXXX. 



