24 ILLINOIS STATE DAIRYMEN'S ASSOCIATION 



factories engaged in the manufacture of skimmilk products, nor 

 the sale of skimmilk when properly labeled ,etc. However, for 

 the purpose of explaining the Babcock test let us consider Rich- 

 mond's definition of milk. He states, ''It is essentially a water 

 solution of milk sugar, albumin and certain salts, holding in 

 suspension small globules of fat, and in a state of semisolution, 

 casein together with mineral matter." To gather together the 

 small fat globules, which number millions to the drop, to mea- 

 sure their volume and thus to determine the percentage of butter- 

 fat is the object of the test. It is based on the treatment of a 

 known quantity of milk with a definite volume of sulphuric acid 

 of given strength in a glass bottle of special shape, with sub- 

 sequent solution of the casein, heating of the mixtxure and lib- 

 eration of the free fat. Then with the help of boiling water and 

 a centrifuge the fat is gathered together in the narrow neck of 

 the bottle, where its percentage is read directly from the special 

 graduations on the neck. 



The easiest way to explain this more in detail is to demon- 

 strate the test step by step. In this work the quantities of milk 

 and sulphuric acid used, the strength of acid used, and all other 

 details have been carefully worked out and must all be carefully 

 observed in order to obtain the best results. 



Steps in Babcock test (demonstrated). 



1. Mix the milk thoroughly. 



This is best done by, pouring from sample bottle into an- 

 other bottle, or other suitable container, and back again several 

 times. I am considering the milk in the sample bottle as being 

 a representative sample from whatever source it may have come. 

 The milk should be at a temperature of sixty tO' sixty-five degrees 

 Fahrenheit. 



2. Fill a 17.6 cubic centimeter pipette to the mark with 

 milk. 



This amount represents eighteen grams of milk or a little 

 more than one-half an ounce. These special pipettes can be ob- 

 tained from creamery supply houses, correctly marked. 



The pipette is best filled in the following manner. Immerse 

 the narrow end of the pipette in the well mixed sample of milk 



