MILK AND YIELD OF CHEESE 205 



the ratio of milk-fat to cheese yield is, therefore, 

 8.31-^3, which equals ^.yy, that is, in this case, one 

 pound of fat in milk is equivalent to 2..^^ pounds of 

 cheese. In the case of milk containing 4 per cent of 

 fat and producing 10.60 pounds of cheese for 100 

 pounds of milk, each pound of fat in milk is equiva- 

 lent to 2.65 pounds of cheese. 



The study of this relation was first undertaken at 

 the New York experiment station to ascertain 

 whether a pound of fat in all normal milks is 

 equivalent to the same amount of cheese. The 

 bearing of this point upon the use of fat in milk as 

 a basis of paying for milk at cheese-factories is 

 obvious. If a pound of fat in milk were always 

 equivalent to the same amount of cheese, then no 

 question could arise as to the strict accuracy of a 

 milk-fat basis in making dividends. If the amount 

 of cheese made for a pound of fat in milk varies, 

 then the fat could not be regarded as a strictly ac- 

 curate measure of cheese yield, and other points than 

 yield would need to be considered, such as the quality 

 of the cheese, in measuring the value of milk for 

 cheese-making. The details of the subject of methods 

 of paying for milk at cheese-factories will be con- 

 sidered later (p. 253). 



We have already seen that the yield of cheese 

 is chiefly dependent upon two constituents of milk, 

 casein as well as fat. It is obvious that if fat and 

 casein were always present in milk in the same 

 relative proportions, then the yield of cheese would 

 always be in the same uniform ratio to milk-fat. 

 But we have found (p. 164) that the ratio of fat 

 and casein in milk varies considerably and, for 



