Relation of Fat to Casein. 163 
who produce the richer milks. If there were a 
quick, accurate method of determining casein, the 
logical practice would be to pay for the milk upon 
the basis of its known content of both fat and 
casein; but failing in that, it is well to examine 
in how far we may fall back upon the percentage 
of fat, the determination of which is both quick 
and accurate, as a measure for determining the 
value of milk for cheese making. While there is 
some disagreement, it seems to be pretty well settled 
that a milk rich in fat is also richer in casein, 
and with milk of ordinary quality, including prob- 
ably nine-tenths of all the milk produced, nearly in 
proportion to the percentage of fat. So that, even 
if the richer milk does yield a little less cheese 
for each pound of fat, the percentage of fat is a 
much more nearly just measure of its cheese-pro- 
ducing power than is the weight of the milk, the 
measure now commonly employed. Further, when 
the milk is so rich in fat that the casein falls 
considerably below its normal ratio to the fat, the 
resulting cheese will be so much richer in fat 
that it will be of considerably better quality, and 
such milk, when pooled with milk poor in fat, will 
so bring up the quality of the whole product, that it 
should be paid for at a correspondingly higher rate. 
The conclusion, therefore, is that the percentage of 
fat is by far the most accurate measure at present 
available for the determination of the cheese-produ- 
cing value of milk, and that milk is practically valu- 
able for cheese making in proportion to the amount 
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