Cream, Testing. 85 



This method does away with the error incident to the 

 adhesion of cream to the side of the pipette, but not 

 with that due to the low specific gravity of the cream, 

 and the results obtained will therefore be too low. 



The dilution of the cream with water in the test bot- 

 tles not only makes it possible to bring into the bottle 

 all the cream measured out, but also insures a clear test. 

 If ordinary cream is mixed with the usual quantity 

 of sulfuric acid used in the Babcock test, a dark-colored 

 fat will generally be obtained, while the cream diluted 

 with an equal or twice its volume of water, when mixed 

 with the ordinary amount of acid, will give a light yel- 

 low, clear column of fat, which will allow of a very 

 distinct and sharp reading. 



The number of bottles to be used for testing a sam- 

 ple of cream by this method must be regulated by the 

 richness of the cream. If the sample probably contains 

 20 per cent, or more, a pipetteful should be divided 

 about equally between three milk test bottles, and two- 

 thirds of a pipetteful of water is added to each bottle. 

 If the cream contains less than 20 per cent, of fat, it 

 will only be necessary to use two milk test bottles, divid- 

 ing the pipetteful between these, and adding one-half 

 of a pipetteful of water to each bottle. 



By using cream test bottles (89), more accurate tests 

 may be obtained in case of cream containing as much 

 as 25 per cent, of fat, by dividing one pipetteful be- 

 tween two bottles, rinsing half a pipette of water into 

 each one, than by adding all the cream to one bottle 

 without rinsing the pipette, for reasons apparent from 

 what has been said in the preceding. 



