68 BACTERIOLOGY. 



ing pneumonia, it has been found in suppurations of 

 the nasal sinuses, empyema, pericarditis, and menin- 

 gitis. No method of immunization has been found as 

 yet. 



THE BACILLUS LACTIS AEROGENES. 



The Bacillus lactis aerogenes is constantly present 

 in milk and, with other micro-organisms, is the cause 

 oi souring. It is also present in water,, sewage, and 

 feces. It closely resembles the colon bacillus, but 

 differs from it chiefly in being non-motile and ha,ving 

 a capsule. It is not a virulent organism, but has been 

 known to be the cause of cystitis. 



THE BACILLI OF THE PROTEUS GROUP. 



The members of this group are putrefactive bac- 

 teria capable of breaking down complex proteids into 

 simpler compounds. They are widely distributed, 

 being found in water, soil, air, and wherever putre- 

 faction is in progress. 



The chief member of the group is the Bacillus 

 proteus vulgaris, a large, thick bacillus that grows 

 readily on the ordinary media. It is motile, but forms 

 no spores. It liquefies gelatin in its growth and pro- 

 duces a characteristic odor of putrefaction. It is not 

 a very virulent organism. It occasionally causes peri- 

 tonitis, endometritis, pyelonephritis, and enteritis. It 

 has been described as the cause of several epidemics of 

 meat poisoning. 



