43 SCIENCE AND PRACTICE OF CHEESE-MAKING 



of water used. A No. 10 brass cartridge shell, on 

 which a wire handle is soldered, is used for meas- 

 uring the sample to be tested and also the alkali. A 

 cartridgeful of milk is placed in a teacup and then 

 a cartridgeful of the alkali solution is added. The 

 contents of the cup are mixed by a rotary motion. 

 If the sample tested remains white, it contains over 

 0.2 per cent of acidity ; if a pink color remains, the 

 acidity is less than 0.2 per cent. The intensity of the 

 pink color indicates the relative amount of acid pres- 

 ent, since the color will be more intense in proportion 

 as there is less acid. Any other measure may be used 

 in place of the brass cartridge-shell, but in every case 

 care must be taken to use equal amounts of milk and 

 of alkali solution. 



This test can be used at the weigh-can in case of 

 milks that are suspected of containing 0.2 per cent or 

 more of acid. 



THE MARSCHALL TEST 



In this test the same general procedure is followed 

 as in the Monrad test, but the rate of coagulation is 

 observed in a different way. The following pieces 

 of apparatus are used: (a) A testing cup or basin, 

 of about a pint capacity, for holding the milk to 

 be tested. On the inside wall of this cup there are 

 graduated spaces beginning with zero at the top and 

 going by half-divisions to 7 near the bottom of the 

 cup, while in the bottom of the cup is a glass tube 

 with a very small bore, (b) An ounce bottle with a 

 mark on it to indicate 20 cc. (c) A spatula for stir- 

 ring the milk, (d) A i cc. pipette. 



