THE VITAL PHENOMENA OF BACTERIA. 55 



as suitable pabulum. I have also succeeded in 

 finding available inorganic sources of oxygen, 

 thereby somewhat complicating the problem. 

 Life processes carried on without oxygen do not 

 effect any profound changes in the organic ma- 

 terial which is broken up, but, in order that 

 the living organism may obtain the requisite 

 quantity of energy from this mode of life, a 

 proportionally large amount of material must 

 be superficially disintegrated. Therein lies 

 the mechanical or dynamic foundation for 

 the fact that a small quantity of a ferment is 

 able to cause the production of much alcohol, 

 butyric acid or lactic acid, and that parasites 

 which have invaded the living body can gen- 

 erate intensely poisonous substances out of the 

 body-proteids. 



In the presence of oxygen the decompo- 

 sition products that are formed by the attack of 

 anaerobic microbes are further decomposed 

 and oxidized by the aerobes ; they are there- 

 by rendered inert and consequently harmless. 

 From alcohol is produced acetic acid and after- 

 wards carbon dioxide ; proteid-like poisons are 

 broken up and oxidized into harmless bodies. 



Some microbes, the obligatory anaerobes, 

 have adapted themselves to the exclusive use 

 of those compounds from which oxygen can be 

 obtained, and others, the obligatory aerobes, are 



