Introduction. 



tion; the speed of the tester, the strength of the acid, the 

 temperature of the milk to be tested, and other points, 

 always require watching, lest the results obtained be too 

 low or otherwise unsatisfactory. In the hands of careful 

 operators the test can, however, always be relied upon 

 to give most satisfactory results. 



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, DeLavaVs 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" 

 (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 is used as in the 



BabcOCk test, and a Small FlG - K The Gerber acid-butyrometer. 



quantity of amyl alcohol is added. The amyl alcohol 

 facilitates the separation of the fat, but introduces 



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 man- 

 ufacturers have prefixed their names; the same applies to the Ahlborn- 

 Babcock method and the Krugmann-Babcock method. 



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



