36. DIRECTIONS FOR MAKING THE BABCOCK 



TEST. 



Illustrative Material: Sample of milk, pipette, test bottles, acid 

 measure, acid, and the Babcock tester; sulphuric acid with a specific 

 gravity of about 1.82. 



Sampling the Milk Great care should be taken to 

 have the sample of milk represent as nearly as possible 

 the whole lot from which it was taken. Milk fresh from 

 the cow, while it is still warm and before the cream has 

 separated in a layer, may be thoroughly mixed by pouring 

 it three or four times from one vessel to another. Sam- 

 ples taken at once from milk mixed in this way give the 

 best results. Milk that has stood until a layer of cream 

 has formed should be poured a greater number of times 

 so that the cream shall be thoroughly broken up and the 

 whole appear like milk. No clots of cream should appear 

 on the surface when the milk is left quiet for a minute. 



Measuring the Milk. When the milk has been well 

 mixed, the milk pipette is filled by placing its lower end 

 in the milk and sucking at the upper end until the milk 

 rises above the mark on the stem; then remove the pipette 

 from the mouth and quickly close the tube at the upper 

 end by firmly pressing the tip of the index finger upon 

 it so the milk cannot flow from the pipette. Holding the 

 pipette up straight, with the mark on a level with the 

 eye, carefully admit air slowly to the space above 

 the milk, till the upper surface of the milk falls to 

 the mark upon the stem. Always have the upper 



