Testing the Acidity of Milk and Cream. 115 



134. Preparation of the solution. The tablet solution 

 formerly used was prepared by dissolving five tablets in 

 50 cc. of water; with 20 cc. of cream each cubic centi- 

 meter of this solution represents .017 per cent, of acid 

 (lactic acid) in the sample tested. The amount of acid 

 in a given sample is then obtained by multiplying the 

 number of cubic centimeters of the tablet solution used 

 by .017. 



135. According to a suggestion made by Mr. C. L. 

 Fitch, 1 the strength of the solution has been changed in 

 such a manner that the percentages of acidity are indi- 

 cated directly by the number of cubic centimeter of tab- 

 let solution used in each test. The solution may be 

 made up in two ways, viz., by use of a 20 cc. or a 17.6 

 cc. pipette. 



a. Use of 20 cc. pipette. When a 20 cc. pipette is used 

 for measuring the sample to be tested, the tablet solution 

 is prepared by dissolving one tablet for every 17 cc. of 

 water; for five tablets 85 cc. of water are therefore taken. 

 When made in this way, each cubic centimeter of solu- 

 tion rep resents. 01 per cent, of acid in the sample tested, 

 10 cc. being equal to .10 per cent, acid, 32 cc. to .32 per 

 cent., 65 cc. to .65 per cent., etc. 



b. Use of 17.6 cc. pipette. The 17.6 cc. Babcock milk 

 test pipette may be used for measuring the sample for 

 acidity testing, and the results read directly from the 

 graduated cylinder, if the tablet solution is prepared by 

 taking one tablet for every 19.5 cc. of water; five tablets 

 are therefore dissolved in 97 cc. of water. 



136. As cream during its ripening process under our 

 conditions generally has from .5 to .6 per cent, of acid 



l Hoard's Dairyman, Sept. 3, 1897. 



