MILK AND ITS CARE. 17? 



In this case it will be observed that the rich- 

 ness of the milk alone is not a fair means of 

 judging the value of the two cows, neither is the 

 amount of milk alone. 



2. The Babcock Method. The method gen- 

 erally used for finding the amount of butter fat 

 in milk and its products is known as the Bab- 

 cock test, and has done more to revolutionize 

 the dairy industry than any other invention ex- 

 cept the centrifugal cream separator. This 

 method was invented by Dr. Babcock, of the 

 Wisconsin Experiment Station, in 1890. It is an 

 accurate, rapid method for finding the per cent, 

 of butter fat in milk, cream, skim-milk, butter- 

 milk, whey, or cheese. In this system sulphuric 

 acid is used to dissolve the solids other than fat 

 in milk, and the fat is then separated by centri- 

 fugal force, and measured on a graduated scale. 

 The apparatus includes the following (Fig. 43) : 

 test-bottles, 17.6 centimeter pipette, acid meas- 

 ure, sulphuric acid, and a centrifugal machine 

 (Fig. 44). 



(i) TEST-BOTTLES. -- The test-bottles are 

 made of strong glass, to withstand sudden 

 changes of temperature. On the neck is a 

 scale graduated from o to 10. Each whole di- 

 vision represents i per cent., and is subdivided 

 into five divisions, each one reading .2 percent. 

 By estimating between divisions, the reading of 

 the test may be made to . i per cent. 



