m] THE CONSTITUENTS OF MILK 39 



which are four or five times the size of the ordinary 

 milk globules, resemble in appearance white blood 

 corpuscles, from which they have been considered by 

 some to be derived. They disappear in milk, as a 

 rule, in from three to fourteen days after calving, but 

 sometimes not till the lapse of a much longer period. 

 The most striking difference, between the composition 

 of colostrum and normal milk, is to be found in the 

 very much larger percentage of nitrogenous matter 

 the former contains. Indeed, the richer quality of 

 colostrum is due almost entirely to this fact, since 

 the other constituents are not in excess of what they 

 are in normal milk. The following is the average 

 composition of the colostrum of 22 cows (Eugling) : 



Water 71-69 



Total Solids .... 28-31 

 Fat . . 3-37 



Casein . . 4-83 



Albumin . 15 '85 



Sugar . . 2-48 



Ash . . 1-78 - 



100-00 



From the above analysis, it will be seen that the 

 increase in nitrogenous matter is due to the albumin, 

 the casein being pretty much the same as in normal 

 milk. Another point in which colostrum differs 

 from normal milk, is the fact that it does not contain 

 milk-sugar, or, if it does, only in mere traces. The 

 milk-sugar is replaced by other kinds of sugar, viz. 



