456 



BACILLUS AEROGENES CAPSULATUS 



thickness about the same as that of the anthrax bacillus ; its ends are 

 square or slightly rounded (Fig. 134). It often occurs in pairs, sometimes 

 in chains ; occasionally filamentous forms are met with. It usually shows 

 a well-marked capsule, hence the name ; it is non-motile and does not 

 form spores. It stains readily with the basic aniline dyes and retains 

 the stain in Gram's method. It grows readily on the ordinary media, 

 but only under anaerobic conditions ; the optimum temperature is that 

 of the body, growth at the room temperature being comparatively slow. 

 In a puncture culture in agar there is an abundant whitish line of growth, 

 with somewhat indented margin ; the individual colonies are white and 

 of rounded or oval form. There is practically no liquefaction of gelatin, 

 though this medium becomes somewhat softened around the growth. 

 In all cases there is a tendency to abundant evolution of gas in the cul- 

 tures, and this is especially 

 marked when fermentable 

 sugars are present. 



The organism appears to 

 be the most frequent cause 

 of rapid gaseous develop- 

 ment in the blood and 

 organs post mortem, this 

 depending upon an invasion 

 of the blood immediately 

 before death. In such cases, 

 even within twenty - four 

 hours under ordinary con- 

 ditions, large bubbles of 

 gas may be present in the 

 veins, and the organs may 

 be beset with gas-contain- 

 ing spheres of various sizes ; 

 the liver is usually the 

 organ most affected, and 

 its appearance has been 



FIG. 134. Bacillus aerogeues capsulatus ; film 



preparation from bone-marrow in a 

 where gas-cavities were present in 

 organs, x 1000. 



case compared to that of Gruy ere 



cheese. The invasion by 

 this organism is met with 

 from time to time in 

 puerperal cases, and also in connection with ulcerative or gangrenous 

 conditions of the intestine ; the bacillus is also found not infrequently 

 in the peritoneum in the cases of perforation. Although the striking 

 changes in the organs are due to a post-mortem development of the 

 bacillus, there is no doubt that its entrance into the blood stream 

 often hastens death, and may in some instances be the cause of it. 

 As already stated, the organism is also met with in some cases of 

 spreading oedema with emphysema as a leading feature. 



When tested experimentally, the bacillus by itself is found to have 

 little pathogenic action. Injection of pure cultures in rabbits and 

 guinea-pigs may be followed by little result, but sometimes in the latter 

 animals "gaseous phlegmon" is produced, without suppuration unless 

 other organisms are present. If a small quantity of culture be injected 

 intravenously, e.g., in a rabbit, and then the animal be killed, bubbles 

 of gas are rapidly produced in the blood and organs, the picture 

 corresponding with that in the human cases. 



