80 AGRICULTURAL BACTERIOLOGY. 



anaerobic or facultative anaerobic bacteria and it does not re- 

 sult in such complete destruction. The final products of 

 putrefaction are still quite complex. Many of them have 

 prominent odors giving the unpleasant smell to the putrefying 

 mass, and many of them are violently poisonous. These same 

 bodies will, under the influence of aerobic bacteria in the pres- 

 ence of oxygen, become still further decomposed. Thus 

 aerobic decomposition may not only check the odors but also 

 destroy the poisons which develop during putrefaction under 

 the influence of anaerobic bacteria. 



The bacteria which contribute to these processes are very 

 numerous. In the early days of bacteriology it was supposed 

 that all such decomposition was commonly produced by the 

 same species of bacterium, and there was described from decay- 

 ing matter a bacterium which received the name of Bacterium 

 termo. This species was the subject of a considerable amount 

 of investigation, was carefully described and many of its prop- 

 erties known. But the improvement of methods of study has 

 disclosed large numbers of bacteria engaged in the process, 



FIG. 12. 



Two species of bacteria found in decaying vegetable tissue. (Ffeiffer.) 



and it is no longer possible to recognize this Bacterium termo 

 of older students. While many bacteria are now known to 

 occur in decaying fluids we do not know what was meant in 

 earlier years by B. termo. 



