154 CANADIAN DAIRYING. 



to it. This is stirred into the milk by means of a spatula. 

 The time at which the rennet was added, and also at 

 which coagulation takes place, are carefully noted. 

 A piece of burnt match or a small stick in the milk 

 helps to note the latter point. The milk should coagu- 

 late in from eighteen to twenty-two seconds, which 

 will allow it to remain in the whey from two and a 

 half to three hours. 



The Monrad and Marchall rennet tests are also used 

 to a limited extent in Canada. 



However, if the ripening of milk is the development 

 of lactic acid, it is important that the degree of lactic 

 acid shall be measured in a more accurate way than 

 can be done by means of a rennet test. The rennet 

 test measures the susceptibility of milk to the action of 

 rennet, and only indirectly does it test the acidity 

 of milk. For this purpose an acidimeter is much 

 more valuable, and it can also be used for measuring 

 the acidity of curd at further stages of cheesemaking 

 instead of using the hot iron test, which is very unre- 

 liable and of little or no value except to experienced 

 cheesemakers. 



The following description of the acidimeter has 

 been prepared by the Dairy School in connection with 

 the Ontario Agricultural College : 



u By the term acidimetry we mean the process of determin- 

 ing the strength of acids, or degree of sourness, as by the use of 

 alkaline solutions. The fact that acids and bases have the power 

 to destroy the characteristic properties of each other is well 

 known. Moreover, from many experiments conducted it has 

 been discovered that the act of neutralization is a definite one ; 



