THE CHEMISTRY OF BACTERIA. 87 



The yeasts, bacteria and moulds were designated as or- 

 ganized ferments because they possess a cell structure, 

 and act on organic matter like the unorganized or soluble 

 ferments secreted in the animal body. There can be no 

 doubt but that the ferment action of living cells, such as 

 yeasts, bacteria, etc., is due to soluble ferments or enzymes 

 which diffuse outward, more or less readily. The uni-cellular 

 organism requires soluble ferments or enzymes, just as do 

 other forms of life. The sprouting seed contains such fer- 

 ments which are necessary to the nourishment of the em- 

 bryo, enabling it to utilize the starch and other stored up 

 foods. Malt, for instance, contains not only an amylolytic 

 ferment, diastase, but also a proteolytic ferment. The yeast 

 cell contains a ferment, which changes glucose into alcohol 

 and carbonic acid. It also contains a peptonizing ferment. 

 Papain, a vegetable ferment, shows a marked proteolytic 

 action. 



Soluble ferments or enzymes are, therefore, produced by 

 plants as well as by animals and are primarily necessary to 

 the absorption of certain foods. 



It will be seen from the above that the soluble ferments 

 or enzymes differ in their action. The more common en- 

 zymes may be grouped or designated according to their 

 characteristic behavior, as: 



Diastatic or amylolytic, 



Peptonizing or proteolytic, 



Fat-splitting, 



Inverting, 



Rennet-like. 



The diastatic ferments are designated thus because they 

 resemble in their action the well known ferment of malt, 

 diastase. Like diastase they split up starch, first into dex- 

 trin, and this in turn is changed into sugar. The saliva and 

 the pancreatic juice contain amylolytic ferments. These 

 compounds are frequently met with in higher plants, cspe- 



