TESTING MILK AND CREAM. 167 



It would appear that the time required for the bottles to stand 

 after the acid is mixed with the milk, would offset that gained 

 by omitting the second whirling which is made in the old 

 method; but the writer has often found it necessary with many 

 kinds of milk, especially with that from cows much advanced 

 in the period of lactation, to allow the bottles to stand a while, 

 even when working the two whirling method, in order to get a 

 clear separation of fat. However, every one who does much 

 testing should have at least two sets of bottles, so there would 

 be no loss of time by this process. When two sets of bottles 

 are at hand one set, charged with the milk and acid, can stand 

 while the second set is being filled, and the second set can stand 

 while the first is being whirled. It is much better to make 

 twelve tests at a time than to make a larger number. Twelve 

 are about all one can easily read off before the fat begins to 

 cool and contract in volume. 



For the above described modification of the milk test no 

 change of apparatus need be made, but the writer, however, 

 prefers to have the base portion of the bottle graduated as before 

 mentioned so no acid measure is required and only one pouring 

 of the acid is necessary. By having the bottle marked at the 

 point A, Fig. 1, at which mark it holds 37.5 cubic centimeters, 

 one can, after the milk is measured in with the pipette, run the 

 acid in until it is filled to this point. It was found impracticable 

 to use a bottle with a smaller base capacity like the cream bottle 

 described farther on, because of the larger amount of curd in 

 milk than in cream and the small size of the neck of the milk 

 bottle necessitating more space for shaking, breaking up the 

 curd and dissolving: it in the acid. 



