8 BUTTER-MAKING AND COMPOSITION OF MILK 



difference in the taste and smell. This indicates that some of 

 the volatile substances are distilled over with the water. The 

 probability is that these flavoring substances are so closely asso- 

 ciated with water in milk that they are inseparable, and that the 

 only place where this water can be prepared so as to assume these 

 qualities is in the cow's udder. The conclusion would then be 

 that the water in normal cow's milk cannot be distilled and 

 replaced by natural water without the loss of the normal good 

 flavor of the product. 



FAT IN MILK 



This is by far the most important constituent of milk, espe- 

 cially to creamery operators. It exists in the milk in suspension, 

 in the form of globules so small as to be invisible to the naked eye. 

 Fat globules, at ordinary living-room temperature, are present in 

 milk in a liquid form. Cooling the milk to a very low tempera- 

 ture (about 50 F.) hardens them. When the globules are caused 

 to unite, as in churning, they also solidify. 



The size of the fat-globules is very minute, and varies con- 

 siderably, according to breeds, individual cows, and the stage 

 in the lactation period. The globules in the milk from the same 

 cow also vary a great deal. Lloyd found fat-globules in Jersey 

 milk to be from 8 to 1 2 micro-millimeters in diameter. Very few 

 were less than 4 micro-millimeters (a micro-millimeter is TTRTO- 

 millimeter, or 25000 of an inch) . The majority of the fat-globules 

 in milk from Shorthorn cows measured from 6 to 8 micro- 

 millimeters in diameter. According to Fleischmann, the size of 

 fat-globules varies between 1.6 micro-millimeters and 10 micro- 

 millimeters in diameter. A Danish investigator maintains that 

 the diameter of fat-globules is between .0063 and .00014 milli- 

 meter, and that i cubic centimeter of milk contains from 2.6 to 

 11.7 million globules. He also asserts that a reflection of the 

 light renders it very difficult to get the proper size of the fat- 

 globules, as the light tends to make the globules appear larger 

 than they are in reality. 



It has been maintained by some that the larger fat-globules 

 contain fats which are different from those contained in the 



