374 



QUARTER-EVIL. 



characters of the cultures, also, resemble those of the bacillus of malig- 

 nant oedema, but the growth in gelatine, before liquefaction occurs, 



has a more compact ap- 

 pearance. It also forms 

 spores, which are usually 

 situated close to the ends 

 of the rods, and are 

 broader than the latter 

 (Fig. 91). It is actively 

 motile, and possesses 

 numerous lateral flagella. 

 The disease can be 

 readily produced in vari- 

 ous animals guinea-pigs, 

 rabbits, etc., by inocu- 

 lation with the affected 

 tissues of diseased ani- 

 mals, and also by means 

 of pure cultures, though 

 a considerable amount of 

 the latter is usually 

 necessary. The condi- 

 tion produced in this way 

 closely resembles that in 

 malignant cedema, though 



there is said to be more formation of gas in the tissues. Rabbits are 

 much more susceptible to this affection than to malignant cedema. 



The disease is one against which immunity can be readily produced 

 in various ways, and methods of preventive inoculation have been 

 adopted in the case of animals liable to suffer from it. This subject was 

 specially worked out by Arloing, Cornevin, and Thomas, and later by 

 others. Immunity may be produced by injection with a non-fatal 

 dose of the virus, or by injection with larger quantities of the virus 

 attenuated by heat, drying, etc. It can be produced also by the pro- 

 ducts of the bacilli obtained by filtration of cultures. 



FIG. 91. Bacillus of quarter-evil, show- 

 ing spores. From a culture in glucose 

 agar, incubated for three days at 37 C. 



Stained with weak carbol-fuchsin. x 1000. 



