Testing the Acidity of Milk and Cream. 135 



By proceeding in the manner described, the man re- 

 ceiving and inspecting the milk at the weigh-can 

 is able to test the acidity of the milk delivered nearly as 

 quickly as he can weigh it ; and according to the results 

 of the test he can send the milk to the general delivery 

 vat or to the pasteurization vat, as the weigh-can may 

 be provided with two conductor spouts. 



149. Size of measure necessary. It is not necessary 

 to use a No. 10 shell for a measure in working the pre- 

 ceding method; one of any convenient size that can be 

 filled accurately and quickly, will answer the purpose 

 equally well, if a measure of the same size is used for 

 both the sample and the tablet solution. Each measure- 

 ful of tablet solution made up as directed, will in this 

 case represent one-tenth per cent, of acid in the sam 

 pie tested. 1 



150. b, Cream. Cream can be tested in the way al- 

 ready described for testing the acidity of fresh milk, by 

 adding to one measureful of cream in the cup as many 

 measures of tablet solution as are necessary to change 

 the color of the cream when the two liquids are thor 

 oughly mixed. If one measure of tablet solution colors 

 one measure of cream, this contains less than .1 per 

 cent, acid; if five measures of tablet solution are re- 

 quired, the cream contains about .5 per cent, acid, etc. 

 By proceeding in the manner described, the operator 

 can estimate the acidity to within .05 per cent, of acid, 

 if half measures of tablet solution are added. The re- 



1 In European creameries and city milk depots the alcohol test is 

 often applied to every can of mms received ; milk that is sufficiently 

 sour to be noticed by the taste, wni coagulate when mixed with an equal 

 volume of 70% alcohol. 



