GENERATION AND DEVELOPMENT 



729 



cent, of palmitin and stearin, 30 per cent, of olein, and 2 per 

 cent, of specific butter fats. 



Milk Sugar or lactose is very liable to undergo fermentation, 

 resulting in the production of lactic acid and the curdling of 

 milk. It is not, however, capable of undergoing direct alcoholic 

 fermentation, which would appear to be a provision against 

 fermentative decomposition occurring either in the gland or in 

 the alimentary canal (Lea). The milk of the mare and cow in the 

 presence of suitable ferments may undergo alcoholic fermenta- 

 tion, as in the production of koumiss and kephir. 



The Salts of milk are principally calcium phosphate, and 

 salts of sodium and potassium. In the composition of the milk 

 an insight is obtained into the nature and quantity of the salts 

 required by growing animals. Bunge gives the following ash 

 analysis of mare's and cow's milk : 



The phosphates are employed mainly in the construction of 

 the skeleton. The excess of potassium over sodium salts is a 

 feature common to many of the secretions of the herbivora, but 

 probably in all animals the ash of milk contains more potassium 

 than sodium. Bunge states that this is due to the fact that as 

 the animal grows it becomes richer in potassium and poorer in 

 sodium salts, depending upon the relative increase in the muscular 

 structure, which is rich in potassium, and the relative decrease 

 in the cartilaginous material, which is rich in sodium. Bunge 

 compared the ash of a puppy with the milk of the mother, and 

 the milk with the blood. It was remarkable how closely the 

 composition of the puppy's system agreed with the salts it was 

 receiving in the milk, though when the ash of the milk was 

 compared with the ash of the blood of the mother, the greatest 

 diversity in composition was apparent. In comparing Bunge's 

 analysis of the ash of cow's and mare's milk, one is struck by the 

 fact that the calf requires much more salts for its nutrition than 

 the foal. 



The first milk secreted is termed Colostrum. The source of 



