CHAPTER V. 
THE BABCOCK TEST. 
This is a cheap and simple device for determining the 
percentage of fat in milk, cream, skim-milk, buttermilk, 
whey and cheese. It was invented in 1890 by Dr. S. M. 
Babcock, of the Wisconsin Agricultural Experiment Sta- 
tion, and ranks among the leading agricultural inventions 
of modern times. The chief uses of the Babcock test may 
be mentioned as follows: 
1. It has made possible the payment for milk accord- 
ing to its quality. 
2. It has enabled butter and cheese makers to detect 
undue losses in the process of manufacture. 
3. It has made possible the grading up of dairy herds 
by locating the poor cows. 
4. It has, ina large measure, done away with the prac- 
tice of watering and skimming milk. 
Principle of the Babcock Test. The separation of 
the butter fat from milk with the Babcock test is made 
possible: 
1. By the difference in the specific gravity of butter 
fat and milk serum. 
2. By the centrifugal force generated in the tester. 
3. By burning the solids not fat with a strong acid. 
Sample for a Test. Whatever the sample to be tested, 
always eighteen grams are used for a test. In testing 
cream and cheese, the sample is weighed. For testing 
milk, skim-milk, buttermilk and whey, weighing requires 
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