126 TEXT-BOOK OF FUNGI 



This amounts to stating that organic ferments are living 

 cells, hence the assumption by Weisner, Pfeffer, and Noll, 

 that alcoholic fermentation is identical with intramolecular 

 respiration. In their action ferments differ from enzymes 

 in splitting up complex organic compounds into several 

 substances of a totally different and less complex nature 

 than the original. During this process there is a libera- 

 tion of gaseous by-products, carbon dioxide being almost 

 constantly evolved. 



Enzymes and ferments agree in one particular : neither 

 body loses its individuality as is the case with an ordinary 

 reagent, when causing a chemical change in a given body 

 to which it is added. 



Yeasts, or species of Saccharomyces^ are characteristic 

 ferments, liberating alcohol and carbon dioxide in varying 

 proportions, depending oh the particular kind of yeast, by 

 acting on hydro-carbon compounds. 



When a hydro-carbon is not present in the first instance, 

 fermentation of a given substance is the joint result of two 

 distinct organisms working in unison. Thus the yeast 

 employed in the production of sake in China consists of an 

 Aspergillus and a Saccharomyces. The former, by means of 

 an enzyme, inverts the rice, and makes it accessible to 

 the ferment furnished by the Saccharomyces. Ward has 

 demonstrated that the so-called ' ginger-beer plant ' is a 

 compound of a Bacillus and a yeast, the work of both 

 being necessary for the production of ginger-beer. It is 

 further stated that a condition of mutualism or inter- 

 dependence exists between these two organisms. 



As opposed to the statement already made that fermenta- 

 tion depends on the presence of living cells, it may be well 

 to note the statement by Biichner, who has separated from 



