THE BABCOCK MILK TEST. 163 



4. Mixing the milk and acid in the test bot- 

 tle. 



5. Adding the hot water, kind of water— hard 

 or soft. 



6. Measuring the fat. 



7. The speed of the machine. 



8. Keep the acid bottle corked when not in 

 use. 



These are not given in the-order of their im- 

 portance, neither are they supposed to cover 

 every difficulty that may be met with in the 

 use of the Babcock test. They represent some 

 things that have had an influence on the proper 

 working of the test and there is a reason for 

 every one of them. 



1. A thorough mixing of the milk, so that the 

 fat is evenly distributed all through the sample 

 to be tested, is sufficiently obvious and needs no 

 explanation. 



2. The intensity of the action of the acid on 

 the milk is shown by the fat separation in the 

 neck of the test bottle, either by the color of 

 the fat or by the black or white stuff that some- 

 times separates at the bottom of the fat column. 

 The black substance is probably charred fat and 

 indicates too strong an action of the acid on 

 the milk. The white adulteration of the fat 

 shows too weak a reaction. The strength, tem- 

 perature, and quantity of the acid used, as well 

 as the temperature of the milk, all have an in- 



