52 CLEAN MILK 



sistency and salty taste. The proteids are at first large in amount 

 and represent albumins and globulins (9 to 10 per cent.) rather thanr 

 casein. For this reason the milk becomes curdled on boiling and 

 this is a test for colostrum ; if it curds on boiling it is unfit for use. 



The sugar in colostrum is not milk sugar, but represents sev- 

 eral other varieties. The percentage of fat is variable, while that 

 of mineral matter is high. Colostrum usually separates into two- 

 layers on standing. Under the miscoscope there are to be seen in 

 it very large globules of fat, called " colostrum corpuscles," and 

 these are characteristic of this form of milk. The colostrum varies 

 in composition from one milking to another after calving, becoming 

 more and more like ordinary milk. 



The following analysis will give an idea of its composition:. 



Per Cent. 



Water 78.7 



Fat 40 



Proteids 14.8 



Sugar 1.5 



Mineral Matters 1.0 



1 00.0 



While the proteids in colostrum are so soluble that they can be 

 absorbed by the calf without any tax on its digestion, and appear 

 to start up digestion in this animal, yet colostrum is not wholesome 

 for man for from five to twenty days after calving. Legal require- 

 ments vary somewhat, but usually demand that cows' milk shall 

 not be sold for fifteen days before, nor from five to twelve days 

 after the calving of the cow supplying the milk. 



The boiling test, referred to above, will show when the milk 

 is fit for human consumption. The milk is not fit for churning 

 until five days after calving, nor from ten to twelve days for making 

 cream cheese. 



Colostral milk and the milk obtained from the cow within 

 fifteen days before calving have produced disease in man. Colos- 



