THE CHEMICAL COMPOSITION OF MILK 37 



hyde and whirling in a centrifugal machine under specified con- 

 ditions, it is possible to effect a nearly complete separation of 

 phosphates from casein. 



4. The data presented, with results of other work, furnish a 

 basis for suggesting an arrangement of the individual compounds 

 contained in milk, especially including the salts. 



COLOSTRUM (Hills) 



Immediately after a birth and preceding the true milk flow, 

 the mammary glands of the mother secrete an acrid, viscid, 

 yellowish fluid, heavier than milk and of alkaline reaction, 

 which is called the colostrum. 



The first fluid given is most markedly colostral in character, 

 the second and succeeding ones less so, until by the sixth to the 

 tenth milking, the true milk flow is usually considered estab- 

 lished and the product used. 



Colostrum differs from milk mainly in containing lees casein 

 and sugar, more ash, many times more albumin, and in con- 

 taining peculiar granules known as "colostrum corpuscles"; 

 its office is purgative, enabling the offspring to rid itself of the 

 accumulations of the foetal bowel. 



The following table gives the average composition of the 

 colostrums of the three cows, analyses being grouped by milk- 

 ings, and the average composition of milk three weeks later. 

 The colostrum analyses are the means of three samples, and 

 each milk, the mean of twelve. None of these first colostrums 

 analyzed so high as they would have done had the cow been 

 milked immediately after calving. 



German analyses give as a maximum of twenty-two cows, 

 milked immediately after calving, specific gravity 1.079, 

 total solids 32.57, fat 4.65, casein 7.14, albumin 20.21, milk- 

 sugar 3.83, ash 2.31. 



