FERMENTS. 481 



with concentrated hydrochloric acid, and hydrochloric gas acid passed 

 into the liquid at degrees, it was shown, after long standing at 10 

 degrees, that the fluid contained both glucosides, maltose and isomaltose, 

 as well as unchanged glucose. The hydrochloric acid makes no distinction; 

 it works with the a as well as the /? form of glucose. That both bioses 

 had, in fact, been formed, was proved by the circumstance that maltase 

 as well as emulsin produced glucose from it. If glucose was kept at 25 

 degrees for two or three months in the presence of yeast maltase, it was 

 shown after removing the unchanged glucose by means of Saccharomyces 

 intermedians, that isomaltose was present. Emulsin produced d-glucose 

 from it, but maltase was unable to do so. When glucose, on the other 

 hand, was acted upon by emulsin, maltose was produced. These relations 

 may be summarized as follows: 



a-glucose 



synthesized by emulsin. 



i 



glucose-a-glucoside (maltose) 



hydrolyzed by maltase. 

 a-glucose 

 /?-glucose 



synthesized by maltase. 

 glucose-/?-glucoside (iso-maltose) 



i 



/3-glucose 



hydrolyzed by emulsin. 



Each of these ferments, emulsin and maltase, builds up that biose which 

 it cannot itself decompose. This synthesis by ferments is, therefore, 

 different as far as our present knowledge goes from that produced by 

 true catalyzer. 



We have gone into these relations in detail in order to show that we are 

 at present not justified in concluding that a single ferment in the cells can 

 effect decomposition or synthesis according to the outer conditions. We 

 have no reason for believing this. This does not, of course, exclude the 

 possibility that these processes may be carried out differently in the cells 

 and tissues. We are, however, not justified in regarding all processes of 

 metabolism in the tissues and cells as being due to fermentation. It is 

 absolutely necessary right at this point to confine ourselves to the facts, 

 and not follow a plausible hypothesis, the value of which is especially 

 problematical here, for there is a vast amount of research to be made. 

 Although our knowledge of fermentation reactions constantly broadens, 

 the great mystery regarding the origin and formation of the ferments 

 remains, and the important question relating to their chemical structure 

 is still unsolved. 



Let us now turn to the classification of the ferments. We have often 



