BACILLUS ^EROGENES CAPSULATUS 



397 



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

 very immune against this disease, whilst they are comparatively suscep- 

 tible to malignant oedema. As in the case of tetanus, inoculation with 

 living spores which have been deprived of adherent toxin by heat does 

 not produce the disease. A toxin can be separated by nitration from 

 bouillon cultures. It is fairly resistant to heat, withstanding two hours 



at 70-75 C. without being 

 destroyed, and it is also 

 very rapid in its action, being 

 capable in appropriate dose 

 of killing a horse in five 

 minutes. 



The disease is one against 

 which immunity can be 

 readily produced in various 

 ways, and methods of pre- 

 ventive 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 (i.e. the 

 oedematous fluid found in the 



FIG. 132. Bacillus of quarter- evil, showing 

 spores. From a culture in glucose agar, 

 incubated for three days at 37 C. 



Stained with weak carbol-fuchsin. x 1000. 



tissues of affected animals and 

 which contains the bacilli), 

 or by injection with larger 

 quantities of the virus at- 

 tenuated by heat, drying, etc. 

 It can be produced also by 



cultures attenuated by heat and by the products of the bacilli obtained 

 by nitration of cultures. An antitoxin has been produced against the 

 toxins of the bacillus, and a method of protection in which the action 

 of this antitoxin is combined with that of the. virus has been used. 

 The antitoxin is said to increase the chemotactic properties of the 

 leucocytes. 



BACILLUS ^ROGENES CAPSULATUS. 



This bacillus, though sometimes aiding in the production of patho- 

 logical changes, is chiefly of interest on account of the extensive gaseous 

 development which it gives rise to in the tissues post mortem. It was 

 described by Welch and Nuttall in 1892 ; it is now recognised as being 

 identical with an organism found in gaseous phlegmon by E. Fraenkel, 

 and called by him the bacillus phlegmones emphyscmatosce. The organism 

 is a comparatively large one, measuring 3 to 6 //, in length and having a 

 thickness about the same as that of the anthrax bacillus ; its ends are 

 square or slightly rounded (Fig. 133). It often occurs in pairs, sometimes in 

 chains ; occasionally filamentous forms are met with. It usually shows 

 a well-marked capsule, hence the name ; it is non-motile and does not 

 form spores. It stains readily with the basic aniline dyes and retains 

 the stain in Gram's method. It grows readily on the ordinary media, 



