6 DEFENSIVE FERMENTS OF THE ANIMAL ORGANISM 



an accurate and possibly exhaustive study of the 

 finer metabolic processes that go on in the cell. In 

 these processes the so-called ferments play the most 

 important role. With their aid we have succeeded 

 in following 1 up, outside the cell, processes which 

 seemed to be exclusive properties of the cell. The 

 more these experiments are extended, the more we 

 meet with observations which show that we have been 

 in the habit of picturing far too schematically the 

 processes within the cell body. Thus, for instance, 

 the simply formulated process of the fermentation of 

 grape sugar into alcohol and carbonic acid gas- 

 C 6 H 12 O 6 = = 2C 2 H 5 OH + 2CO 2 has been found to 

 be a most complicated process. A whole chain of re- 

 actions takes place, before the grape sugar is finally 

 converted into alcohol and carbonic acid gas. There 

 are many more intermediate stages present than 

 were ever suspected. It will be an important duty 

 of future research to ascertain what importance 

 alcoholic fermentation, in all its stages, has for the 

 yeast cell. We are indebted to recent researches, 

 in which Knoop, Neubauer, Friedmann, Embden, 

 Dakin, Schittenhelm, Jones and others have taken 

 a prominent part, for a knowledge of numerous 

 intermediate stages in the decomposition of the 

 ammo-acids, of grape sugar, of purin bases, &c. 

 Every time we demonstrate fresh intermediate links 

 in the decomposition of certain compounds we get a 



