ii6 Transactions of the Canadian Institite. [Vol. VII. 



3. This function consists in eliminating certain forms of bacteria and 

 fungi by the lactic acid formed, and providing an acid nutrient medium 

 upon which on!}' such bacteria and fungi can thrive as can withstand 

 the acid or consume it. The micro-organisms which consume the acid 

 prevent its accumulation in too strong a degree, take part in the 

 peptonizing and flavour producing processes, and enable other bacteria 

 or fungi, whose activity was weakened by the acid, to continue their 

 work. 



4. The specific character of a particular kind of cheese depends 

 upon the predominating form of micro-organism, which the manner of 

 preparation and the handling of the cheese have brought about. 



Boekhout and Vries made Edam cheese from pasteurised milk 

 inoculated with a lactic acid ferment isolated from Edam cheese, but 

 this cheese failed to ripen. 



Cheese made from pasteurised milk and inoculated with a plug of 

 fourteen da)^ old cheese did not ripen, and the same result took place 

 with cheese made from pasteurised milk and mixed with five per cent, 

 market milk. 



Better cheese was made from milk heated to 55" C. for half an hour 

 and treated exactly as in the above experiments, but even this cheese 

 could not be called normal. 



Then these investigators attempted to get milk as germ free as 

 possible, by washing the hind quarters of the cow with soap and water, 

 followed by three per cent, boracic acid. The milker's hands were 

 similarly treated. The milk obtained was not quite sterile, but so 

 poor in bacterial content that a portion remained a long time in the 

 incubator at 22 C. without change. 



This milk was divided into two equal portions without the addition 

 of any cultures, and this part acted as a check on the other portion with 

 which the following three experiments were made : 



1. Milk inoculated with fourteen da}' old cheese. 



2. Milk inoculated with a lactic acid bacterium isolated from Edam 

 cheese. 



3. Milk inoculated with market milk. 



In numbers one and three experiments, there was a normal ripening, 

 but the cheese made from milk inoculated with the lactic acid bacillus 

 failed to ripen. 



