72 



Testing Milk and Its Products. 



i 



( 



83. Bartlett's modification. Bartlett 1 proposed a modifi- 

 cation of the method of procedure in the Babcock test, which 

 aims to simplify the manipulations. 20 cc. of acid are added, 

 instead of 17.5 cc., and the bottles filled with the milk-acid 

 mixture are left standing for not less than five minutes and then 

 filled with hot water to within the scale; the bottles are then 

 whirled for five minutes at the regular rate (52). 



83a. Siegfeld's modification. The 

 German v dairy chemist Siegfeld in 

 1899 proposed a modification of the 

 Babcock test, 2 using 2 cc. of amyl .alco- 

 hol with the sulfuric acid, and filling 

 up with dilute sulfuric acid (1:1, sp. 

 gr., 1.5) in one filling, in place of 

 water after the whirling. A clear 

 separation of the fat is facilitated by 

 both these changes, but when properly 

 conducted there is no difficulty what- 

 ever in obtaining a clear fat column 

 in the BabcocK test as described in 

 this book, and the modification has not 

 therefore been generally introduced in 

 American factories. It has, however, 

 been adopted in many German creamer- 

 ies where the Babcock test is used. 



84. Bausch and Lomb centrifuge. 

 Fig. 29 shows a form of hand centri- 

 fuge which may be used to advantage 

 by physicians or in pathological labora- sian test, 

 tories for the determination of fat in 



Test bottle m ^- The centrifuge is especially designed for ex- 

 amination of urine, sputum, blood, etc., but has 

 been adapted to milk analysis by the Leffmann & 

 Beam test, a special form of bottle (fig. 30) having been con 

 stn.icted for this purpose. The machine gives satisfactory re- 

 sults by the Babcock test as well, provided the acid used is 

 1.83-1.84, or if the bottles containing the acid-milk mixture be 

 placed in hot water for five or ten minutes prior to the whirling. 



1 Maine experiment station, bull. 31 (s. s.) 



2 Molkerei Ztg., 1899, p. 51. 



Flu. 28. 



used in t In- 

 Russian test 



