94 



Testing Milk and Its Products. 



This test bottle is more fragile and expensive than 

 the ordinary Babcock bottles, and must be carefully 

 handled; it is now generally made of heavier glass 

 than formerly, and this form is to be highly recom- 

 mended. 1 



100. The double-size skim milk bottle which was the 

 first one recommended for the testing of skim milk, is of no 

 particular value. It is difficult to obtain a thorough mixture of 

 the milk and the acid in these bottles, and the tests invariably 

 come too low, more so than with the regular Babcock bottles or 

 double-necked skim milk bottles, for reasons 

 that are readily seen. 



101. Buttermilk and whey. The 

 testing of buttermilk by the Babcock 

 test offers no special difficulties if the 

 special directions for testing skim milk 

 are followed ; what has been said in re- 

 gard to tests of separator skim milk is 

 equally true in case of this by-product. 

 Whey contains only a small quantity 

 of solids not fat, viz., less than 7 per 

 cent. (27), and the mixing with acid 

 and the solution of the whey solids 

 therein is therefore readily accom- 

 plished; the acid solution is of a light 

 reddish color, turning black but very 

 slowly. 



102. Butter. Butter is not so easily tested as other 

 dairy products, both because of the difficulties in ob- 

 taining a fair sample, and on account of the high per- 

 centage of fat it contains. Butter is a mechanical mix- 



1 A double-necked copper test bottle with a detachable graduated 

 glass neck was designed and tried by one of us a fcvr years ago, but It 

 was not found to possess any special advantage over the glass bottle. 



FIG. 38. 

 The double-bore 

 skim milk bottle. 



