RECEIVING, SAMPLING, AND GRADING. 



85 



There are two tests commonly used for determining fat in 

 milk, viz., the Babcock and Oil-test Churn. The latter method 

 is rapidly giving way to the former. The Babcock tes; is un- 

 doubtedly superior, though many still prefer the Oil-test, 



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Hi 



Fig. 30.— 17.6 c.c. 

 pipette. 



milk Fig. 31. — Automatic 

 17.6 c c. pipette. 



J 

 Fig. 32 — Automatic 

 Russian pipette. 



The Babcock method of testing consists of taking 18 grams of 

 the substance to be tested into a special graduated bottle as 

 shown in illustration. Milk is measured out with a pipette hold- 

 ing 17.6 c.c. Cream, butter, and cheese, or any other substance 

 which cannot be measured accurately, should be weighed. 

 The measured quantity of milk in the bottle is then digested by 

 adding 17.5 c.c. of commercial sulphuric acid having a specific 

 gravity of about 1.82. The acid digests all proteids and sets 



