BACILLUS AEROGENES CAPSULATUS 133 



Pathogenesis. Bacillus aerogenes capsulatus may cause emphysematous 

 gangrene when it gains entrance into body tissue at the site of an injury. It 

 probably is capable of producing gastro-intestinal disturbances. Relatively, 

 the pathogenic power of bacillus aerogenes is slight; several cubic centimeters of 

 a bouillon culture injected into the circulation of a rabbit frequently fails to 

 produce ill effect. Guinea-pigs seem most susceptible, yet some strains are 

 not pathogenic for these animals. 



Diagnosis. The morphology, and character of growth in agar and gelatin 

 stab cultures, is usually sufficient to establish the identity of this organism. 

 When further studies are desirable and when the bacillus is found, associated 

 with other organisms and needs be isolated, a bouillon culture is made. Three 

 to 5 cc. of an i8-hour-old culture is injected, intravenously, into a rabbit. About 

 15 minutes after inoculation the rabbit is killed with ether or chloroform and 

 placed in an incubator at 37C. Twelve to 18 hours later the rabbit will appear 

 much distended with gas. Crepitation is felt in the subcutaneous tissue due 

 to accumulation of gas. If the peritoneal cavity is opened by puncture and a 

 flame touched to the escaping gas it will burn with a blue flame. Cultures made 

 from the blood, liver, heart and other organs will yield pure cultures of the 

 bacillus aerogenes capsulatus. 



