544 BACTERIOLOGY. 



in or near the middle of the body of the rods. The 

 spores vary in length and are oval in form, being often 

 of greater diameter than the bacilli, to which they give 

 a more or less oval or spindle shape. 



The bacilli stain readily by the usual aniline colors 

 employed, but are decolorized by Gram's method. 



Biological Characters. A strictly anaerobic, liquefy- 

 ing, motile bacillus. Forms spores. It grows, however, 

 in all the usual culture media in the absence of oxygen. 

 Development takes place at the room-temperature, but 

 more rapidly and abundantly at 37 C. 



Growth in Gelatin. This bacillus may be cultivated 

 in ordinary nutrient gelatin, but the growth is more 

 abundant in glucose-gelatin containing 1 or 2 per cent, 

 of glucose. Gas-bubbles are formed and the gelatin 

 liquefies. 



Growth on Agar. On agar plates the colonies appear 

 as dull, whitish points, irregular in outline, and when 

 examined under a low-power lens are seen to be com- 

 posed of a dense network of interlacing threads radi- 

 ating irregularly from the centre toward the periphery. 



Blood-serum is rapidly liquefied, with the production 

 of gas. Cultures of the malignant oedema bacillus give 

 off a peculiar, disagreeable odor. 



Pathogenesis. The bacillus of malignant oedema is 

 especially pathogenic for mice, guinea-pigs, and rabbits, 

 although man, horses, dogs, goats, sheep, calves, pigs, 

 chickens, and pigeons are also susceptible. A small 

 quantity of a pure culture injected beneath the skin of 

 a susceptible animal gives rise to an extensive hemor- 

 rhagic oedema of the subcutaneous connective tissue, 

 which extends over the entire surface of the abdomen 

 and thorax, causing hypersemia and redness of the 

 superficial muscles. There is no odor developed, and 



