448 



MALIGNANT (EDEMA 



guinea-pigs, with garden soil. The bacillus is also often present 

 in the intestine of man and animals, and has been described as 

 occurring in some gangrenous conditions originating in connec- 

 tion with the intestine in the human subject. 



Microscopical Characters. The bacillus of malignant oedema 

 is a comparatively large organism, being slightly less than 1 //, 

 in thickness, that is, thinner than the anthrax bacillus. It 

 occurs in the form of single rods 3 to 10 ju in length, but both in 

 the tissues and in cultures in fluids it frequently grows out into 

 long filaments, which may be uniform throughout or segmented 



at irregular intervals. In 

 cultures on solid media it 

 chiefly occurs in the form 

 of shorter rods with some- 

 what rounded ends. The 

 rods are motile, possessing 

 several laterally placed 

 flagella, but in a given 

 specimen, as a rule, only 

 a few bacilli show active 

 movement. Under suit- 

 able conditions they form 

 spores, which are usually 

 near the centre of the rods 

 and have an oval shape, 

 their thickness somewhat 

 FIG. 131. Bacillus of malignant oedema, exceeding that of the 

 showing spores. From a culture in i . n /5. -, QA IQI\ 

 glucose agar, incubated for three days bacillus (Figs. 130, 131). 

 at 37 C. The bacillus can be readily 



Stained with weak carbol-fuchsin. x 1000. stained by any of the basic 



aniline stains, but loses the 



colour in Gram's method, in this way differing from the anthrax 

 bacillus. 



Characters of Cultures. This organism grows readily at 

 ordinary temperature, but only under anaerobic conditions. In 

 a puncture culture in a deep tube of glucose gelatin, the growth 

 appears as a whitish line giving off minute short processes, the 

 growth, of course, not reaching the surface of the medium. 

 Soon liquefaction occurs and a long fluid funnel is formed, with 

 turbid contents and flocculent masses of growth at the bottom. 

 At the same time bubbles of gas are given off, which may split 

 up the gelatin. The colonies in gelatin plates under anaerobic 

 conditions appear first as small whitish points which under the 

 microscope show a radiating appearance at the periphery, re- 



