New YorK AGRICULTURAL EXPERIMENT STATION. 279 
essential basis in enabling us to pass judgment upon the methods 
in question. 
(1) The relation of fat in milk to cheese yield. 
(2) The relation of milk-constituents to composition of cheese. 
(3) The relation of the composition of cheese to its quality. 
ti RELATION... OF (/FATSRIN, MILK ~1Q)\(MEESE YIELD; 
Much study has been given, especially at this Station, to the 
quantitative relations existing between the percentage of fat in 
milk and the yield of cheese, or the amourt of cheese correspond- 
ing to one pound of fat in milk. The relation is a very simple one 
to calculate and is found by dividing the number of pounds of 
cheese made from 100 pounds of milk by the number represent- 
ing the percentage of fat in milk. For example, the yield of cheese 
from 100 pounds of milk containing 3 per ct. of fat is 8.31 pounds; 
the ratio of milk-fat to cheese yield is, therefore, 8.31--3, which 
equals 2.77; that is, in this case, one pound of fat in milk is equiva- 
lent to 2.77 pounds of cheese. In the case of milk containing 4 
per ct. of fat and producing 10.60 pounds of cheese for 100 pounds 
of milk, each pound of fat in milk is equivalent to 2.65 pounds 
of cheese. 
The study of this relation was first undertaken at this Station 
to ascertain whether a pound of fat in all normal milks is equiva- 
lent 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 equiva- 
lent 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 accurate measure 
of cheese yield, and other points than yield would need to be con- 
sidered, such as the quality of the cheese, in measuring the value 
of milk for cheese-making. 
Our work has shown that the yield of cheese is chiefly depend- 
ent upon two constituents of milk, casein as well as fat. It is ob- 
vious 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 that 
the ratio of fat and casein in milk varies considerably and, for 
this reason, the ratio of milk-fat to yield of cheese must also vary. 
