Relation of Fat to Casein 239 



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 



