252 DAIRYING. 



A CHAPTER ON MILK TESTING.* 



The Babcock milk test is the quick and simple method 

 of determining the fat content of milk which has been 

 most generally adopted in this country. The test was in- 

 vented by Dr. S. M. Babcock, of Wisconsin Agricultural 

 Experiment Station, and was first published in July, i8go. 

 The following is an outline of the method: 



A known quantity of milk (17.6 cubic centimeters, or 

 about f of an ounce) is pipetted off into a graduated test- 

 bottle; 17.5 cc. of commercial sulfuric acid, of a specific 

 gravity of 1.S2 to 1.S3, is then measured out by means of 

 a graduated cylinder or an automatic pipette, and added to 

 the milk. The two fluids are mixed, and when the curd is 

 dissolved, the test-bottles are placed in a centrifugal ma- 

 chine and whirled for 4 minutes at a rate of 800-1200 revo- 

 lutions per minute, the small hand-machines on the market 

 requiring the higher number of revolutions. Boiling hot 

 water is then filled into the bottles, by which means the 

 liquid fat is brought into the narrow graduated neck of the 

 bottles ; after an additional whirling of the bottles for a 

 minute, the length of the column of fat is read off in per 

 cent. 



The whole process of testing a sample of milk according 

 to this method will take less than a quarter of an hour 

 when a little skill in manipulation has been reached. 



The various dealers in dairy implements have placed 

 Babcock machines on the maiket in sizes fiom 4- to 60- 

 bottle machines, and supply the necessary outfit, as test- 

 bottles, pipettes, graduates, and sulfuric acid. There are 

 at present three different types of machines: hand-machines 

 (friction or cog-wheel machines; the latter ones are to be 

 preferred, and have now practically replaced the friction 

 machines), steam turbine, and belt-power machines. The 

 Facile, Twentieth Century, and Agos Babcock testers are 



* The subject of milk testing is treated exhaustively, and detailed direc- 

 tions for using the Babcock test are given in Farrington-Woll, Testing 

 Milk and its Products, Menduta Book Co., Madison, Wis., 21st Editiun, 

 1912. 



