ANALYTIC PROCESSES 1 9 



a small amount of amyl alcohol with an equal 

 volume of hydrochloric acid was added to the 

 milk, and the proteins thus coagulated dissolved 

 by strong sulfuric acid. About the same time 

 Babcock devised a process in which sulfuric acid 

 was used alone. Subsequently Gerber published 

 a process in which the essential feature of the 

 Leffmann-Beam method, namely, the use of amyl 

 alcohol, was advised. 



The test-bottles have a capacity of about 30 c.c. 

 and are provided with a graduated neck, each 

 division of which represents 0.1% by weight 

 of butter fat. 



15 c.c. of the milk are measured into the 

 bottle, 3 c.c. of a mixture of equal parts of amyl 

 alcohol and strong hydrochloric acid added, 

 mixed, the bottle filled nearly to the neck with 

 concentrated sulfuric acid, and the liquids mixed 

 by holding the bottle by the neck and giving it a 

 gyratory motion. The neck is now filled to 

 about the zero point with a mixture of sulfuric 

 acid and water prepared at the time. It is then 

 placed in the centrifugal machine, which is so 

 arranged that when at rest the bottles are in a 

 vertical position. If only one test is to be made, 

 the equilibrium of the machine is maintained by 

 means of a test-bottle, or bottles, filled with a 

 mixture of equal parts of sulfuric acid and water. 

 After rotation for from one to two minutes, the 



