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 anaérobic, 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 cedema bacillus give 
off a peculiar, disagreeable odor. 
Pathogenesis. The bacillus of malignant cedema 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 cedema of the subcutaneous connective tissue, 
which extends over the entire surface of the abdomen 
and thorax, causing hyperemia and redness of the 
superficial muscles. There is no odor developed, and 
