CHAPTER XXVII 



THE SPORE-BEAEING RODS— THE GENERA BACILLUS AND 

 CLOSTRIDIUM. ANTHRAX, BLACKLEG, MALIGNANT 

 EDEMA, TETANUS, BOTULISM, AND GASEOUS EDEMA. 



Thp bacteria belonging to this group are all rod-shaped 

 organisms capable of producing endospores. They differ 

 considerably in size, cultural characteristics, shape and 

 position of spores, motility and fermentative reactions. 

 The group includes practically all of the spore-bearing 

 bacteria. 



The genus Bacillus includes those organisms which are 

 aerobic or facultative anaerobic, the genus Clostridium 

 those which are anaerobic and micro-aerophilic. Most of 

 the bacteria, but not all, belonging to the group are Gram- 

 positive, although there is considerable variation in the 

 rapidity with which decolorization will take place. 



One member of the genus Bacillus, Bacillus anthracis 

 (the cause of the disease anthrax in cattle), and several 

 members of the genus Clostridium will be considered. The 

 most important of the species of Clostridium are Clostrid- 

 ium tetani, causing tetanus or lockjaw in man and animals, 

 Clostridium chauvcei, causing blackleg in cattle, the organ- 

 ism causing botulism, Clostridium hotulinum, and a group 

 of organisms found associated with gase6us edema, the most 

 important of these being Clostridium welchii. 



Bacillus anthracis 



Synonym. — Bacterium anthracis. 



This organism is the specific cause of the disease known 

 as anthrax or splenic fever in cattle. In man the disease is 



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