Milk and Milking. 11 



Further albuminoids of milk, but of secondary im- 

 portance, are lactoglobulin, lactalbumen and peptone, 

 the nutritive value of which is, however, considerably 

 impaired by boiling the milk, by which a greater part 

 is changed to hemialbuminose. 



Following the albuminoids, the different fats in 

 milk merit our attention ; we designate them collec- 

 tively as butter-fats, and find them suspended in the 

 milk in emulsive condition, that is, globules of the 

 minutest size ; these globules, coated with casein, give 

 the white color to milk. The size and number of 

 globules is variable in one and the same animal, being 

 affected by the advance of lactation, change of feed 

 and by sickness. With the advance of lactation, the 

 number of large globules diminishes and that of the 

 small globules increases ; with the change from dry 

 feed to green feed in the spring, there is an increase 

 in the proportion and the number of the large globules. 

 Disease or sickness and the use of cow 7 s for draft, 

 when not accustomed to it, has a marked effect in 

 diminishing the number and size of globules. Suc- 

 culent food decreases the size and increases the num- 

 ber of globules ; oats, bran and linseed meal increase 

 their size. Age is apparently without effect. Morn- 

 ing's milk has larger globules than evening's milk. 

 The first part of the milking has fewer and smaller 

 globules than the last. 



Butter-fat is liquid at from 85 to 105 F., when 

 cooled below 00 it becomes of a crumbly consistency ; 

 notwithstanding milk may be cooled to 32 without the 



