TESTING MILK BY RENNET-EXTRACT AND PEPSIN 123 



in case the temperature drops, it can be raised by plac- 

 ing the basin of milk in warm water. In ordinary 

 cheddar cheese-making, milk is ready for the addition 

 of rennet when it coagulates in 30 to 60 seconds un- 

 der the foregoing conditions. 



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 (Fig. 47) 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 be- 

 ginning with zero at the 

 top and going by half-divis- 

 ions to 7 near the bottom 

 of the cup, while in the bot- 

 tom 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 stirring the milk, (d) A I cc. 

 pipette. 



The operation of conducting this test is as follows: 

 Measure with the pipette I cc. of the rennet-extract 

 used and empty it into the ounce bottle, previously 

 half rilled with clean cold water. Rinse the pipette 

 two or three times by drawing water into it from the 

 bottle and allowing it to run back into the bottle. Mix 

 well by shaking. Then place the milk to be tested 



FIG. 47 

 MARSCHALL RENNET-TEST 



