io6 Transactions of the Canadian Institute. [Vol. VII. 



2. The greater number of species. 



3. The relation of the peptone gelatine liquef}'ing to non-liquefying 

 colonies (1:300 to 1:600 in Emmenthaler against 1:90 to i:20O in Cottage 

 cheese). 



The bacterial content of Emmenthaler was shewn to grow during 

 the ripening process from 90,000 to 850,000 and finally he ascribed to 

 the liquefying germs the role of ripening the cheese. 



Adametz also demonstrated that when disinfectants like Thymol 

 and Kreolin were mixed with the curd, the ripening process was totally 

 checked. The same result ensued from attempts to ripen Hauskase 

 (Cottage chee.se) in an atmosphere of Carbon disulphide. 



De Freudenreich by the use of better methods, such as the employ- 

 ment of whe}' peptone gelatine, and more accurate triturations obtained 

 much higher figures than Adametz. He followed, step by step, the 

 ripening of a single cheese, in order to see if the changes the cheese 

 passed through were the work of special microbes, and to see if the 

 species present at the commencement of ripening continued active until 

 the end of the process. The cheese was analysed at intervals of eight 

 to fifteen days, and like Adametz he found in fresh cheese many 

 different micro-organisms which quickly disappeared as the cheese aged, 

 so that at the end of eighteen days, a microbe called Bacillus x, by the 

 author, predominated in the culture plates ; and at the end of sixty-four 

 days, only this bacillus was found. The analyses were continued until 

 the 155th day when the ripening was perfect. The cheese at this time 

 contained 1,662,500 bacteria per gramme, all being Bacillus x. The 

 highest number counted was 8,975,000 when the cheese was fifty-two 

 days old, but there were considerable fluctuations in the numbers 

 found. 



The Bacillus x was a true type of lactic acid germ, somewhat similar 

 to Adametz' No. xix, and forming, like it, lactic acid. 



De Freudenreich described minutely the morpholog}^ physiological 

 properties, and the resistence of this germ to desiccation and chemical 

 agents, and in the end came to the following conclusions : 



1. The ripening of cheese was the work of bacteria; without bacteria 

 there was no ripening. 



2. Two periods could be distinguished in the ripening : the first 

 characterized by the presence of many species, and the second dis- 

 tinguished by the predominance of one bacterial species. In most cases 



