ON MILK AND MILK-TESTING 43 



pipette into the vessel. The quantity of milk de- 

 livered from the pipette should just balance the 18 

 grams placed on the other side of the scales. 



How may the acid measure be calibrated? 



1. By running into the measure from a gradu- 

 ated burette 17.5 c. c. water. The upper surface 

 should then just reach the 17.5 mark. 



2. Balance the measure on a scale and place 17.5 

 grams weight on the opposite side. Then fill the 

 measure to the mark with water. The weight of 

 the water should just balance the 17.5 gram weight. 



What forms of acid measures are used? 



1. A glass cylinder holding 17.5 c. c. 



2. The Swedish acid bottle and 17.5 c. c. pipette 

 combined. 



What acid is used in the Babcock test? 



Sulphuric acid, with a specific gravity of 1.82 to 

 1.83 and strong enough to produce a light yellow 

 color in fat. 



What substances other than acids are sometimes 

 used? 

 Solvents like ether, alcohol, or petroleum spirits 

 may be used to bring the fat into solution and 

 separate it from the milk serum. 



What are the principal reasons for using an acid in 

 testing fat? 



I. To destroy the sugar and films of casein that 

 entangle the fat. 



