CHAPTER XIII 



ANAEROBIC ORGANISMS 



TETANUS THE ANAEROBES OF WOUNDS GAS GANGRENE 

 B. BOTULINUS BLACK QUARTER ANAEROBIC BUTYRIC 

 ACID ORGANISMS. 



ANAEROBIC organisms vary in their tolerance to free oxygen 

 from facultative anaerobes to strict anaerobes. Some have 

 supposed that even the strict anaerobes require for intensive 

 growth a very small trace of oxygen. Some of the strict anaerobes 

 in some circumstances (e.g. in sulphindigotate broth) seem to be 

 able to develop more or less aerobically, and may also be " edu- 

 cated " to grow aerobically. An anaerobe, e.g. B. perfringens, 

 which will not grow in glucose broth under aerobic conditions, 

 may do so if a piece of potato be added to the medium (Wright). 

 It is probable that the organism locates itself in nooks and crannies 

 in the potato, where it finds approximately anaerobic conditions 

 and so is able to develop. 



The anaerobic organisms have assumed considerable importance 

 owing to the occurrence of several species in septic wounds, 

 particularly lacerated wounds and compound fractures caused by 

 shrapnel, etc., where they induce serious conditions tetanus, gas 

 gangrene, septic infection and the like. 



Anaerobic organisms are common in soil, in decomposing 

 organic matter and in the intestine of man and animals, and it is 

 chiefly from the soil, particularly if highly cultivated and manured, 

 that wounds derive their infection. The anaerobes seem to play 

 a considerable part in Nature in the breaking down of organic 

 matter and are regarded as the principal agents in liquefying the 

 solid material of the sewage in the septic tank of a bacterial 

 system of sewage purification. 



The chemical reactions which take place during the growth of 



