PATHOGENIC BACTERIA. 



269 



readily cultivated by Buchner's 

 method for anaerobes. It grows 

 best at the body temperature, but 

 will grow at the room tempera- 

 ture. It may liquefy gelatin 

 slowly or not at all. The growths 

 are whitish. In media containing 

 lactose, dextrose, or saccharose it 

 produces an abundance of gas ; but 

 it is also, according to Welch, 

 able to form gas from proteids. 

 Milk is coagulated, and the re- 

 action becomes acid. Gas forms 

 upon potato, where the growth 

 is thin and grayish-white. 



It occurs in the intestine of 

 man and various other animals, 

 in soil, sewage and water. It is 

 not usually pathogenic to rabbits 

 and mice. In guinea-pigs, spar- 

 rows and pigeons it may produce 

 " gas phlegmons." It has been 

 found on numerous occasions in 

 the organs of human cadavers 

 in which a development of gas 

 had taken place, producing bub- 

 bles or cavities in the tissues, im- 

 parting to them a peculiar spongy 

 character (German, Schaumor- 

 gane). Probably this is as a rule 

 a post-mortem invasion, but there 

 is reason to believe that in some 

 cases it enters the circulation dur- 

 ing life. It has been found in 



FIG. 68. 



cases of emphysematous gangrene gas-bubbles. 



Bacillus aerogenes capsulatus, 

 culture in dextrose-agar showing 



