STUDIES IN FERMENTATION 71 



views of Pasteur in regard to molecular asymmetry 

 and life. Moreover, fermentation being a method 

 of splitting up organic compounds is a valuable 

 instrument for studying the relationship of the 

 asymmetry of an organic compound and the asym- 

 metry of its derivatives if they possess any. In 

 fermentation Pasteur surmised there might be fur- 

 nished the clue to many problems not only in chem- 

 istry, but also in biology, if only the confusion and 

 obscurity surrounding the subject could be dis- 

 pelled. 



Pasteur's early studies were made on lactic acid 

 fermentation, the process which is responsible for 

 the souring of milk. His memoir on the subject, 

 though short, is very noteworthy, not only in estab- 

 lishing for the first time some important facts, but 

 in containing the expression of several of the lead- 

 ing ideas which guided him throughout his future 

 investigations. Pasteur observed that the little 

 gray patches which appeared on the bottom and 

 sides of the vessels of fermenting fluid were com- 

 posed chiefly of minute organisms, much smaller 

 than yeast plants, and that these organisms in- 

 creased in number as fermentation proceeded. Are 

 they the agents that cause the souring of milk, as 

 yeast plants produce alcohol from sugar? Pasteur 



