Generation and Development. 393 



ring in them, culminating in the production of milk at the 

 birth of the young animal. 



The earliest milk is termed the Colostrum. It is a peculiar 

 yellowish-white fluid, of alkaline reaction, sweetish taste, 

 and remarkable for the amount of proteid it contains ; for 

 instance, in the cow, the colostrum contains 15 per cent, of 

 proteid, whilst the normal milk only contains 4 per cent, 

 to 5 per cent. 



If the fluid be examined microscopically, it is found to be 

 filled with bodies termed 'colostrum corpuscles.' These 

 are large granular corpuscles filled with fat, which has not 

 yet escaped from the parent cell. 



The use of colostrum is to act as a natural purge, and so 

 clear out the intestinal canal of the young animal. 



Milk. — This follows the secretion of colostrum. It is a 

 slightly alkaline fluid, soon showing an acid reaction, with 

 a specific gravity in the cow of 1028 to 1034 The following 

 analysis of cow's milk and colostrum from the same animal 

 is given by Halliburton : 



Milk. Colostrum. 



Water- - - - 84-28 787 



Solids- - - 15-72 21-3 



Casein - - - 3-57 7"3 



Albumin - - - '75 7'5 



Fat - - - - 6-47 4-0 



Lactose - - - 4*34 1*5 



Salts - - - - -63 1-0 



Specific gravity - - 1028-1034 1046-1065. 



The same authority also quotes analyses of the milk of 

 other animals : 



Mare. Sheej>. Ass. 



Water - - 92*5 - 18-24 - 90-5 



Solids - 7-5 15-17 - 9-5 



Casein - - 1*3 ) 



Albumin - "3 ) 



4-7 - 1-7 



Fat - -6 4-8 - 1-4 



Lactose - 4'7 - 3-4-6 ) 



Salts - - -3 - -6 .• 



f.--' 



The proteids of milk are casein (which clots on the 



