American Tests. 47 



milk. In the next two years no less than seven dis- 

 tinct methods were devised by chemists of Agricul- 

 tural Experiment Stations for this purpose. All of 

 them were much better than any that had hitherto 

 been known, but one was so much in advance of 

 any of the others that now it is practically the only 

 method used for the quick determination of fat in 

 milk. This is the method devised by Dr. S. M. Bab- 

 cock, known as the Babcock test, and first published 

 in July, 1890. The various tests, in the order of 

 their publication, were as follows : 



SJiorVs method. — This method was invented by 

 F. G. Short, at that time chemist of the Wisconsin 

 Agricultural Experiment Station, and was first pub- 

 lished in Bulletin 'No. 16 of the Wisconsin Agricul- 

 tural Experiment Station for July, 1888. In brief, 

 the method consisted in converting the fat in the 

 milk into a soap by means of an alkali, and then dis- 

 solving the soap by an acid, setting free the fat. 

 The process was rendered complete by boiling for 

 several hours. The determination was made with a 

 measured quantity of milk in a glass test bottle with 

 a narrow graduated neck, into which the fat was 

 raised at the end of the process and read off volu- 

 metrically. Considerably difficulty was often ex- 

 perienced in getting a clear separation of the fat 

 from the contents of the tube. The long period of 

 boiling was also an important drawback to the 

 method. 



The method of Failyer and Willard .—T\vi^ method 

 was devised by Professors Failyer and Willard, of 



