84 Testing Milk and Its Products. 



dilution of the cream with water in the test bottles 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 

 nearly 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 1 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. 



94. Use of a 5 cc. pipette. When the cream is in good con. 

 dition for sampling, satisfactory results can also be obtained by 

 the use of a 5 cc. pipette, provided great care is taken in mix- 

 ing the cream before sampling; 5 cc. of cream are measured into 



