8 



tity of sulphuric acid. The acid performs other functions 

 than the simple solution of the serum solids. Much heat 

 is developed by its action, and this causes the fat globules 

 to lose their individuality and run together, a condition 

 which greatly facilitates the separation from the serum, 

 and this separation is still further accelerated by the 



= 





FIG. 1. Old type of 

 Babcock milk-test 

 bottle. 



FIG. 2. Type of Babcock 

 milk-test bottle conforming 

 to the requirements of the 

 United States Bureau of 

 Standards, and showing 

 graduations. 



increase in specific gravity of the serum caused by the 

 presence of the heavy sulphuric acid. When the solution 

 of the serum solids is effected, the complete separation of 

 the fat and serum is accomplished by whirling in a centri- 

 fuge. The fat is gradually driven into the graduated neck 

 of the bottle and the percentage read directly. 



