43^ SCIENCE AND PRACTICE OF CHEESE-MAKING 



pains must be taken to keep the tube open, since a lit- 

 tle dirt quickly stops it. The Marschall test is con- 

 venient for ordinary work, but is not capable of as 

 great delicacy as is the Monrad test. Results obtained 

 by different workers can be compared by the Monrad 

 test, but not by the Marschall test 



THE MONRAD TEST 



This test is based upon the amount of time required 

 for a definite quantity of milk at a given temperature 

 to become coagulated by a fixed quantity of rennet. 



The pieces of apparatus required are the following: 

 (i) A tin cylinder for measuring milk, holding, when 

 full, 1 60 cc, (2) a 5 cc. pipette, (3) a 50 cc. glass 

 flask, (4) a thermometer, and (5) a half-pint tin basin. 



In testing the ripeness of milk by means of rennet- 

 extract, one first prepares a dilute solution of the 

 rennet, as follows : One measures with the small pi- 

 pette 5 cc. of rennet-extract into the 50 cc. flask. The 

 pipette is then rinsed twice with water by sucking it 

 full of cold, clean water to the mark, the rinsings also 

 being run into the 50 cc. flask. The flask is then filled 

 with water to the 50 cc. mark, and the contents are 

 well mixed by shaking. The next step is to fill the 

 tin cylinder with the well-mixed milk to be tested and 

 this is emptied into the half-pint basin. The milk 

 must be at the temperature at which one adds the 

 rennet in cheese-making, which is generally about 

 84° to S6° F. To the milk at the desired tempera- 

 ture, one adds 5 cc. of the diluted rennet solution, 

 mixes it through the milk quickly, using the ther- 

 mometer as a stirrer. The exact time when the 



