330 SUGAR DESTRUCTION IN THE ECONOMY 



observers, 8 in their control tests of his statements (with 

 provision of thorough asepsis), failed to obtain any fermen- 

 tation. "The fact," states Vernon, 9 "that Stoklasa and 

 his collaborators were unable to find any bacteria by their 

 cultures does not necessarily prove that they were not pres- 

 ent. As far as can be made out from their studies the 

 cultures, as a rule, were placed in aerobic surroundings, al- 

 though the fermentations were anaerobic. The cultural con- 

 ditions were, therefore, not favorable for the growth of 

 the bacteria which occasion the alcoholic fermentation." 

 Harden and Maclean, 10 who have recently subjected the work 

 of Stoklasa to severe criticism, found that if to solutions 

 of glucose they add tissue juices, or sediments obtained 

 therefrom by alcoholic ether, in the course of the first few 

 hours a very trivial gas development takes place, the cause 

 of which is purely physical, and which is noticeable both 

 when there is no sugar present and when disinfectants 

 are added. Later on, however, a gas production begins, 

 continuously increasing in intensity, which goes on in pro- 

 portion to the growth of bacteria. If toluol be added in 

 quantities which are harmful to bacteria but which are 

 known from experience to be without influence upon the 

 zymases, the gas formation ceases. That the test for bac- 

 teria in Stoklasa 's experiments so frequently resulted nega- 

 tively, may, in the opinion of these authors, have been due 

 to the fact that it was made at the end of the fermentation, 

 therefore at a time when the bacteria may have been al- 

 ready destroyed by the concentration of their own metab- 

 olic products (alcohol, lactic acid). 



However highly Stoklasa 's discoveries as to the impor- 

 tance of zymases in the anaerobic respiration of plants may 

 be regarded, it must be said that analogous processes in the 



Battelli, Maze", Portier, Cohnheim, Embden, Arnheim and Rosenbaum, 

 Harden and Maclean. 



H. M. Vernon, Ergebn. d. Physiol., 9, 205, 1910. 



10 A. Harden and H. Maclean (Lister Instit.), Jour, of Physiol., 42, 64, 1911. 



