a4U APPLIED BACTERIOLOGY 



capable of converting an unlimited amount of alcohol. The 

 conversion of cellulose into carbonic acid and marsh gas 

 (methane) by the putrefactive organisms is a case of simple 

 hydrolysis, as will be seen from the following formula : 



(CeH.oOs)^ + nH,0 = SnCOa + 3„CH, 



Cellulose. Water. Carbonic Methane, 

 acid. 



These ' soluble ' ferments are divisible into a number of 

 groups, the five most important of which are the following : 



1. Proteolytic. — Those which change proteids into 

 proteoses and peptones, as in the case of trypsin and 

 pepsin. 



2. Amylolytic. — Those which change amyloses (starch, 

 glycogen) into sugars, such as diastase, ptyalin, and 

 amylosin. 



3. Inversive. — Those which convert the saccharoses, 

 such as lactose, maltose, cane-sugar, etc., into glucose. 

 Invertin, which occurs in the cells of yeasts and in the 

 intestinal juice, is an example of this class. 



4. Goagulative. — Those which convert soluble into in- 

 soluble proteids, such as rennet (chymosin), fibrin, and 

 myosin ferment. 



5. Steatolytic. — Those which split up fats into fatty acids 

 and glycerine. Steapsin, which occurs in the pancreatic 

 juice, is an example of this class. 



Proteolytic Enzymes. — The proteolytic or albumen -dis- 

 solving ferments are a very common product of bacterial 

 growth. The liquefaction of the gelatine, which is allied 

 to albumen in chemical composition, which is caused by so 

 many of the bacteria, is certain evidence of the presence of 

 an enzyme of this class. The proteolytic ferment excreted 

 by bacteria is more of the nature of trypsin than pepsm, 

 since the liquefaction of gelatine takes place in a medium 



