234 PRINCIPLES AND PRACTICE OF MILK HYGIENE 
making the test. The acid dissolves the solids not fat 
and liberates the fat from its emulsion, generates heat 
which causes the fat globules to run together, and in- 
creases the specific gravity of the serum. The test is 
made as follows: The temperature of the milk should 
CURUTETRaT eRe | 
ved 
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1 
Fia.33.—Moderntypeof Babcock milk- Fra. 34.—Pipette used in Babcock 
testing bottle conforming to the require- _ testfor measuring milk. ‘From Chem- 
ments of the U. S. Bureau of Standards. ical Testing of Milk and Cream, by 
From Chemical Testing of Milk and R.H.Shaw, U.S. Dept. of Agriculture.) 
ream, by R. H.Shaw, U.S. Dept. of Ag- 
riculture.) 
be between 60° and 70° F. After the milk has been 
thoroughly mixed, the tip of the pipette is inserted just 
beneath the surface and filled to the 17.6 cc. mark. 
The pipette is then inserted obliquely into the mouth of 
the bottle and the milk permitted to run slowly down 
the inside of the neck. When the milk ceases flowing, 
the pipette is blown into to force out any residue. To 
