THE COMPOSITION OF MILK 25 



the table below, which is taken from Gottlieb's analyses : 



Each number represents the average of four analyses 

 taken several days apart. Each sample came from a 

 young woman who had been confined a few months 

 before. 



It has often been said that casein in human milk dif- 

 fers chemically from that of cow's milk; but, as stated 

 above, according to the investigations of recent years, 

 there is good reason to believe that this is not the case. 

 (Hammersten, Cohnheim.) 



Sow's milk is thick, slimy and of alkaline reaction. In chemical 

 composition it is very variable, especially so in regard to the fat 

 content which varies between 1.0 per cent, to more than 12.0 per cent. 

 In some of the analyses reported, it appears that a distinction has 

 not been made in relation to the proportion of fat of the milk 

 that was drawn first and that drawn last, but since the other 

 ingredients of the milk were found in different proportions, the 

 variation can not be doubted. The quantity of protein averages 

 about 6.0 per cent, but may vary from 5.7 to 15.5 per cent. The 

 quantity of lactose varies from 2.0 per cent, to 3.8 per cent., the 

 ash from 0.77 per cent, to 1.18 per cent. On the whole, it may be 

 said that sow's milk is quite concentrated. 



Bitch's milk is also quite variable in its composition. The 

 fat content varies between 4.0 per cent, and 12.0 per cent., the pro- 

 portion of casein between about 3.5 per cent, and 6.0 per cent., 

 albumin is present in about the same quantity as casein, there is 

 about 2.0 per cent, to 3.0 per cent, of lactose and about 1.0 per 

 cent, of ash. 



The milk of the cat has not received much study. According 

 to some analyses that have been made (by Comaille), it is of about the 



