CHAPTER XXXIV 



GROUP OF SPORE-BEARING ANAEROBES 



THE six organisms belonging to this group are Bacillus tetani, 

 causing tetanus; B. chauvcei, of blackleg; B. gastromycosis ovis, 

 of bradsot; B. cedematis, of malignant edema; B. welchii, of em- 

 physematous edema; and the B. botulinus, of meat-poisoning. 



The organisms of this group are united because of their lack 

 of tolerance of free oxygen. They will develop in the presence of 

 small amounts of oxygen, but not with an oxygen pressure as 

 great as that of the atmosphere. Morphologically, these organ- 

 isms are not unlike. All are bacilli producing spores. Other 

 characters, such as retention of Gram's stain and motility, are 

 inconstant. The members of this group may be differentiated 

 from each other in most cases by their morphological and cultural 

 characters, although, for the separation of some, animal experi- 

 mentation is necessary. 



Bacillus tetani 



Synonym. Bacillus of Nicolaier. 



Disease Produced. Tetanus or lockjaw in man and animals. 



Nicolaier, in 1889, observed the Bacillus tetani in pus from 

 laboratory animals that had died, following subcutaneous inocula- 

 tion with small amounts of garden-soil. He cultivated the organ- 

 ism, but did not succeed in securing it in pure cultures. Kitasato, 

 in 1889, succeeded in growing the organism in pure culture, and in 

 transmitting the disease experimentally. Kitasato and Veyl, 

 in 1890, described the production of the tetanus toxin. 



Distribution. The organism is found in all parts of the world. 

 It is particularly common in street-dust and fertilized garden-soil, 

 and is found quite constantly in the alimentary tract of herbivor- 

 ous animals. It seems probable that it may for a time main- 

 tain a saprophytic existence and multiply in the soil. 



349 



