ON MILK AND MILK-TESTING 57 



chemical analysis that about one-tenth of i per 

 cent will not rise. When credit is given for the 

 curved spaces that are not occupied by fat at the 

 ends of the fat column, the results agree closely 

 with chemical analysis. 



How should skim milk be tested for fat? 



In the same manner as whole milk, excepting 

 that a special double-neck test bottle is used. 

 About I to 1.5 c. c. extra amount of sulphuric acid 

 is used, and the machine should whirl the bottles 

 about a minute longer than usual. The fat per- 

 centage is read on the graduated part of the small 

 neck. 



How are buttermilk and whey tested for fat? 



In the same manner as skim milk, excepting 

 that it is not necessary to use more than 17.5 c. c. 

 of sulphuric acid. 



How should cream be tested for fat? 



By weighing accurately a representative sample 

 of the cream into a special cream test bottle, and 

 then following the method used for testing whole 

 milk. 



How may a proper sample of cream be secured? 



By pouring the cream from one vessel to another 

 and having all lumps of dried cream thoroughly dis- 

 tributed and reincorporated. Then take the sample 

 with a sampling tube, or, if one cannot be secured, 

 use a dipper to transfer the cream to the sample 

 bottle. 



