Babcock's method) is to dissolve the casein by a strong acid 

 say H 2 SO 4 of sp. gr. r82. When their action goes on, 

 there is a great rise in temperature, the fat liquifies and when 

 submitted to the centrifugal force it all comes to the surface 

 and is measured in the graduated neck of the test bottle. 

 The fault in these systems lies in the fact that owing to the 

 great rise in temperature due to a strong acid being mixed 

 with the milk, some of the fat, with milk-sugar, gets charred 

 to a black substance which consequently interferes with the 

 obtaining of accurate results. 



1. 1 20. Gerber's method overcomes this difficulty by the 

 addition of amyl alcohol, and it is at present considered the 

 best and quickest volumetric test for milk-fat. 



1.121. The first stage in the process is sampling of the 

 milk by tilting it from pail to pail until the cream is well 

 distributed throughout the whole. The sampling should be 

 done when the milk is still warm from the cow. 



1.122. A number of safety pipettes are then got ready, 

 i.e., 10 c. c. pipettes for acid, 1 1 c. c. pipettes for milk, and 

 r c. c. pipettes for amyl alcohol ; also test bottles fitted with 

 rubber corks and chemicals for test. 



1.123. The sulphuric acid used should be of the sp.gr. 

 1*82 ; a little more or less does not matter. 



1.124. First of all, loc. c. of the sulphuric acid are taken 

 in a pipette. Then the test bottle is inverted in a stand and 

 the acid is run into it. The drop or two of acid remaining 

 in the tip of the pipette is not to be blown in. Next is put 

 in i c. c. of amyl alcohol (on the top of the acid), which 

 will slightly discolours when coming in contact with the acid. 

 The greatest possible care must be observed in measuring the 

 amyl alcohol, as an extra drop or two affects the result most 

 remarkably. It does not matter so very much if a slight 

 error is made in the measuring of the milk or the acid. 



1.125. Next, the milk is to be let in from the pipette drop 

 by drop, Having put in the measured proportions of all 



