Introduction. 



10. Foreign methods. In European countries four 

 practical milk and cream tests, besides the Babcock test, 

 are in use at the present time, viz.: Gerber 's acid- 

 butyrometer, the lactocrite,De Laval's butyrometer, and 

 Fjord's centrifugal cream 

 test. 1 



Of these the last test 

 given has never, to our 

 knowledge, been intro- 

 duced into this country, 

 and the first three only 

 on a small scale. 



11. The Gerber method 2 



(fig. 1) is essentially the old 

 Beimling method (7), worked 

 out independently by the 

 Swiss chemist, Dr. N. Gerber. 

 In this test sulfuric acid of 

 the same strength as in the 

 Babcock test is used, and a 

 small quantity of amyl alco- 

 hol is added. The amyl alcohol facilitates the separation of the 

 fat, but may introduce a source of error on account of impuri- 

 ties contained therein, when the results obtained with a new lot of 

 alcohol can not be checked against gravimetric analysis or against 

 tests made with amyl alcohol known to give correct results. This 

 method is, however, extensively used in European countries, hav- 

 ing there practically replaced the Babcock test or been adopted 

 in preference to it. 



12. The Lactocrite was one of the earliest practical milk 

 tests introduced. It was invented by De Laval in 1886. The 

 acids used in this test are lactic acid (originally, acetic acid) 



1 The Lister- Babcock milk test advertised in English papers and 

 known as such in England, is the regular Babcock test, to which the 

 English manufacturers have prefixed their name; the same applies to 

 the Ahlborn- Babcock method and the Krugmann- Babcock method. 



2 Gerber, Die praktische Milchpriifung, 7th edition, 1900. 



Fig. 1. The Gerber acid- 

 butyrometer. 



