16 PROFITABLE DAIRYING 



the serum, but the fat floats in the serum in the 

 form of very small particles varying in size and 

 number in different kinds of milk. The number 

 of fat globules in a cubic millimeter, which is 

 about the size of a pinhead, is from one to five 

 million, depending, of course, upon the kind of 

 milk. Ordinary milk contains about two million 

 fat globules to the drop, and it has been esti- 

 mated that it would take a man ten years to 

 count the number in a cubic centimeter of milk, 

 counting at the rate of one hundred per minute, 

 for ten hours per day. 



Fat globules. When first drawn the fat glob- 

 ules are uniformly distributed, but after standing 

 a few minutes these globules gather into groups 

 of ten to one hundred, although we find through- 

 out the milk small, isolated, individual globules. 

 Their average diameter is about one ten-thou- 

 sandth of an inch. Some are so small, however, 

 that they appear under a microscope as very tiny 

 specks, too small to be measured. 



Size and number of fat globules. The number 

 of fat globules increases as the period of lacta- 

 tion advances, there being from two to three 

 times as many in the same volume at the end as 

 at the beginning. The size, however, greatly 

 diminishes. The fat. globules in milk of different 

 breeds vary in size, the largest ones being found 

 in Jersey milk. The Ayrshire and Holstein- 



