312 



THE CHEMICAL COMPOSITION OF MILK. 



cells like bunches of grapes. These are from 0-005 to 0-025 milli- 

 metre in diameter, and are detected easily under the microscope. 

 They do not disappear entirely from milk till three weeks after 

 calving, according to Henle. 



The specific gravity of colostrum is from 1-046 to 1-079 at 

 15 C. (59 F.), and averages 1-068. 



Engling gives the following composition : 



Per cent. Per cent. Per cent. 



Water, -. . . 76-60 to 67-43 average, 71-69 

 Fat, . . .1-88,, 4-68 



Casein (?), . . . 2-64 7-14 

 Albumin (?), ' . . 11-18,, 20-21 

 Sugar, . . . 1-34,, 3-83 



Ash, 



1-18 



2-31 



3-37 

 4-83 

 15-85 

 2-48 

 1-78 



Change of Colostrum to Normal Milk. The composition 

 of colostrum changes rapidly after parturition. Houdet gives 

 the following figures as illustrating the change (Table LXX.) : 



TABLE LXX. 



These figures show a sudden increase in the amount of proteins 

 over that contained in the fluid secretion described above. 

 Houdet ascribes this to a diversion to the udder of nutritive 

 material which up to this time had been supplied to the foetus. An 

 increase of fat and a decrease of soluble proteins are also observed. 



The colostrum from another cow was examined at intervals 

 after parturition with the following results (Table LXXI.), 

 which show the gradual transition into normal milk : 



TABLE LXXI. CHANGE OF COLOSTRUM TO NORMAL MILK. 



