s 



Testing Milk and Its Products. 



a source of error which may become serious, and espe- 

 cially so, where the results obtained with a new lot of 

 amyl alcohol can not be compared with gravimetric 

 analysis or with tests made with amyl alcohol known to 

 give correct results. This method is, however, exten- 

 sively used in several European countries, having there 

 practically replaced the Babcock test or been adopted in 

 preference to it. 



12. The Lactorite was one of the earliest practical 

 milk tests introduced. It was invented by De Laval in 

 188G. The acids used in this test are lactic acid (origi- 

 nally, acetic acid) with a mixture of hydrochloric and 

 sul f uric acids. This test is now but rarely met with, 

 even in Europe, having been largely replaced by the 

 following method. 



13. In the De Laval butyrometsr (fig. 2) the same acid 

 is used as in the Babcock test, but the tubes employed and 

 the manipulations of the method differ materially from 



Fi. 2. DeLaval's butyrometer. 



