442 



QUARTER-EVIL 



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

 more resistant to this disease, whilst they are comparatively suscep- 

 tible to malignant osdema. 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 

 cultures of bouillon containing 5 per cent, glucose and a thick emulsion of 

 sterile calcium carbonate. 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. It is to be noted as an important fact, that while fresHy 

 isolated cultures possess a high degree of virulence they may have little 



capacity for in vitro toxin 

 production. Grassberger and 

 Schattenfroh state that there 

 may be an antagonism be- 

 tween maximum virulence 

 and maximum toxin produc- 

 tion. One of the properties 

 of the toxin is said to be a 

 capacity for killing leuco- 

 cytes. 



The disease is one against 

 which immunity can be pro- 

 duced in various ways, and 

 methods of preventive inocu- 

 lation 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. 

 FIG. 129. Bacillus ot quarter-evil, showing 



s^^r^ u <r - 



Stained with weak carbol-fuchsiu. xlOOO. the . intravenous and intra- 



peritoneal routes) with a non- 

 fatal dose of the virus (i.e. 



the cedematous fluid found in the tissues of affected animals and which 

 contains the bacilli), or by injection with larger quantities of the virus 

 attenuated 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 (cf. Anthrax, 

 p. 348). The antitoxin is said to increase the chemiotactic properties of 

 the leucocytes. 



BACILLUS AEROGENES CAPSULATUS. 



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

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

 development to which it gives rise 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 emphysematosce. The organism 

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



