40 Report of the Chemist of the 



or less water in cheese, regardless of the composition of the milk 

 used, so long as the milk is normal. In studying vaiiations 

 found in the cheese-producing constituents of milk, we need, 

 therefore, to consider only the fat and casein. 



The fat which forms so large a proportion of natural butter 

 comes from the fat in milk, and it is this same milk-fat that forms 

 the fat of cheese. 



Casein, in an impure form, is familiar to everj' one under the 

 name of curdled milk. When milk sours, a white, solid sub- 

 stance or curd forms, and this substance is called casein, though, 

 strictly, it is a compound of casein and something else. In using 

 the term casein we do not include albumen and albumose, as is 

 commonly, though erroneously, done, but refer only to the com- 

 pound that is coagulated by rennet and retained in cheese. 



2. Variations in Amount of Fat in Milk. 

 We shall give the detailed results secured with the fifty dif- 

 ferent herds, whose milk was examined during the season, and 

 shall then give a general summary, showing the average varia- 

 tions of the milk of all the herds from month to month during 

 the season. 



