This is found in certain cases of disease in cattle, having a rapid course and nearly always a fatal issue. The disease has several names, such as "Black-leg," "Quarter evil," and, in Germany, "Rauschbrand".

The bacilli are thickish rods, which are mostly single. They have lively motion by means of numerous cilia. The bacillus grows readily on ordinary media, but it is strictly anaerobic. It produces spores which are thicker than the bacillus and lie nearer one end than the other, so that a somewhat club-shaped form is produced. It produces gas in stab-cultures, and is decolorized when treated by Gram's method, in both these respects contrasting with bacillus anthracis.

Fig. 145. - From same preparation as Fig. 144, more highly magnified. The bacilli visible as definite rods. x 700. (Koch).

The bacillus is pathogenic in cattle, sheep, goats, and guinea-pigs. No case has been observed in the human subject. Guinea-pigs, sheep, and cattle have been rendered immune by inoculation of a virus of diminished intensity.