i8o 



BACTERIA 



FIG. 63. B. Aerogenes capsulatis, , . . 

 agar culture showing gas formation, birds. 

 (Williams.) 



agar strict anaerobic conditions 

 are necessary for growth, gas bub- 

 bles appear in the media, and 

 the agar may be forced out of the 

 tube in stab cultures. In bouillon 

 it grows under anaerobic condi- 

 tions. The growth is rapid, 

 bouillon is clouded, and a froth 

 appears on the surface. After a 

 few days the media becomes clear, 

 owing to the sedimentation of the 

 bacilli. Growth occurs best in 

 sugar bouillon, which becomes 

 strongly acid. In milk the growth 

 is rapid and luxuriant; the pro- 

 teids are coagulated. Anaerobic 

 conditions must be observed. On 

 potato it grows well, producing 

 bubbles in the water which may 

 cover the potato in the tube. The 

 growth appears thin, moist, and 

 grayish-white. 



Pathogenesis. The pathogenic 

 properties of this organism are 

 limited. It is not able to endure 

 the oxygen of the circulating blood. 

 Grows best in old clots, and in 

 the uterus. It produces gas rapidly 

 in some cases of abortion and in 

 peritonitis in man, which is quickly 

 followed by death. It causes gase- 

 ous phlegmons in guinea pigs, and 

 injections are usually fatal to 

 In man infection has fol- 



