164 AMERICAN DAIRYING. 



fluence on the action of the acid on the milk. 

 Too strong acid and warm acid or milk may be 

 the cause of the black stuff in the fat. Hence 

 it may be advisable to use a little less acid, or 

 cool either the milk or acid, or both, before 

 mixing the two liquids in the test bottle. On 

 the other hand if a white curdy substance sep- 

 arates with the fat this may be remedied by 

 using a little more than the graduated full of 

 acid or by warming the milk or acid 10 to 20 

 deg. before making the test. None of these 

 precautions will be necessary if the acid has a 

 specific gravity of 1.82 and both milk and acid 

 are at 60 to 70 deg. Fah. when used. 



3. When measuring the acid into the test 

 bottle hold it at an angle which will cause the 

 acid to follow the inside walls to the bottom 

 and not drop through the milk in the center of 

 the bottle, because by the latter way of pouring 

 the acid a portion of the milk may be acted on 

 by the strong acid before it is diluted by the 

 water of the milk. This makes a more intense 

 action of the acid on a small part of the milk, 

 and the fat it contains is somewhat decomposed 

 and blackened. This black substance is then 

 separated with the fat by the usual method of 

 finishing the test. If properly poured into the 

 test bottle there will be a distinct layer of milk 

 and acid with little or no black color between 

 them. 



