BUTTER. 2^1 



prepared by dissolving one tablet in one ounce of water. 

 This is the standard. Four ounces of the tablet solution are 

 made by filling a four-ounce bottle with water and adding 

 to it four tablets. The No. lO shell is filled with the milk 

 or cream to be tested. This measured quantity is poured 

 into a white cup. The same measure is then filled with 

 the tablet solution and this is poured into the cup. The 

 two liquids are thoroughly mixed and the color of the mix- 

 ture is noted. If there is no change of color, another 

 measure of tablet solution is added. This is continued 

 until the sample which is being tested becomes of a pink 

 color. As soon as the pink color is obtained no more tablet 

 solution is added. The per cent of acid in the sample 

 tested is found from the number of measures of tablet 

 solution it is necessary to add to one measure of the 

 sample in order to produce the pink color. Each measure 

 of tablet solution represents one tenth of one per cent 

 acid. 



A more exact testing of acidity can be made by using a 

 17.6-cc. pipette for measuring the milk or cream to be 

 tested and a loo-cc, graduated cylinder for the tablet solu- 

 tion. 



Five tablets are dissolved in 97 cc. of water in the 

 cylinder, and this solution is gradually poured into the 

 17.6 cc. of milk or cream in a white cup. When sufficient 

 tablet solution has been added to produce the pink color in 

 the sample tested, the operator observes on the scale of 

 the graduated cylinder the number of cc. tablet solution 

 used. Each cc. of this tablet solution is equal to 0.0090 gr. 

 lactic acid, and when 17.6 cc. of a sample is tested, each cc. 

 of the tablet solution is equal to .01 per cent acid in the 

 sample. 



Milk does not smell or taste sour until it contains 

 about three-tenths of one per cent acid. It has been 

 found, however, that milk containing over two tenths per 

 cent acid cannot be safely pasteurized, because such milk 

 sours very soon. These tablets supply a quick means of 

 selecting the sweetest of different lots of sweet milk, by 

 showing which contain less than two tenths of one per 

 cent acid. 



