442 BACTERIOLOGY. 



everywhere present in the soil. In certain respects it 

 is a little like the bacillus of anthrax, and was at one 

 time confounded with it; but it differs in the marked 

 peculiarity of being a strict anaerobe. It was first 

 observed by Pasteur, but it was not until later that 

 Koch, Liborius, Kitt, and others described its peculi- 

 arities in detail. It can usually be observed by insert- 

 ing under the skin of rabbits or guinea-pigs small por- 

 tions of garden earth, street dust, or decomposing 

 organic substances. There results a widespread oedema, 

 with more or less of gas production in the tissues. In 

 the oedematous fluid about the seat of inoculation the 

 organism under consideration may be detected. (Fig. 

 94, A.). 



Pia. 94. 





^, 



V^" 



Bacillus of malignant cedema. 



A. Bacilli in short and long threads in oedematous fluid from site of inocu- 

 lation of guinea-pig. (After Koch.) 



B. Spore-stage of the organism ; from culture. 



It is a rod of about 3 to 3.5 fi long and from 1 to 

 1.1 // thick— ?.e., it is about as long as the bacillus 

 anthraois, but is a trifle more slender. It is usually 

 found in pairs, joined end to end, but may occur as 

 longer threads; particularly is this the case in cultures. 



