SAPROGENS AND PATHOGENS 2$ 



(pepsin, diastase). The latter " exercise solely a hydrolytic 

 action" (Fischer), causing the molecules of insoluble compounds 

 to take up water and to separate into less complex molecules of a 

 different constitution, which are soluble in water. The organized 

 ones act differently. Highly complex molecules are split up, and 

 numerous substances of a totally different character are formed 

 with the evolution of gases and by-products (Fischer). The 

 reason for this is, perhaps, to be found in the supposition that 

 the bacteria abstract oxygen for their own use, and thus cause the 

 atoms to unite into an entirely different substance. According 

 to the above-named investigator, it is not possible to express 

 such chemical changes by a simple equation. Experiments have 

 shown that B. typhosus and pyocyaneus are able to split up olive 

 oil or fat, and produce glycerine and fatty acids, thus making 

 them accessible to fermentation (Fischer). The action of the 

 buttermilk organisms, while usually very complex, may be 

 represented by the following : 



Ci 2 H 22 On + H 2 O = C 6 H 12 O 6 + C 6 Hi 2 O 6 



lactose galactose dextrose 



C 6 Hi 2 O 6 = 2C 3 H 6 O 3 



galactose lactic acid 



Saprogens produce putrefaction which is the chemical trans- 

 formation of albuminous bodies with the evolution of nitrogen, 

 and of alkaloidal substances, known as ptomaines. Aromatic 

 elements are also produced, such as indol, phenol, kresol, etc. 



It is therefore obvious that fermentation and putrefaction are 

 separate processes, the former an action upon carbohydrates, 

 the latter a splitting up of proteins. If has been found that when 

 organisms can attack both substances, the sugars and starches 

 are first broken up; this is what is meant when it is stated that 

 carbohydrates have a "sparing action" upon proteins. 



Pathogens. If the tissues are receptive to bacteria, and if the 

 latter, in any way, injure the tissues, then the invading organism 

 is called pathogenic. Theoretically the tissues of the body are 



