400 MALIGNANT (EDEMA. 



Immunity. Malignant oedema was one of the first 

 diseases against which immunity was produced by injec- 

 tion of toxines. The filtered cultures of the bacillus in 

 sufficient doses produce death with the same symptoms 

 as those caused by the living organisms, but a relatively 

 large quantity is necessary. Chamberland and Roux 

 (1887) found that if guinea-pigs were injected with several 

 non-fatal doses of cultures sterilised by heat or freed from 

 the bacilli by filtration, immunity against the living or- 

 ganism could be developed in a comparatively short time. 

 They found that the filtered serum of animals dead of the 

 disease is more highly toxic, and also gives immunity when 

 injected in small doses. These experiments have been 

 confirmed by Sanfelice. 



Methods of Diagnosis. In a case of supposed malignant 

 oedema, the fluid from the affected tissues ought first to be 

 examined microscopically, to ascertain the characters of the 

 organisms present. Though it is not possible to identify 

 absolutely the bacillus of malignant oedema without culti- 

 vating it, the presence of spore-bearing bacilli with the 

 characters described above is highly suspicious (Fig. 100). 

 In such a case the fluid containing the bacilli should be 

 first exposed to a temperature of 80 C. for half an hour, and 

 then a deep glucose agar tube should be inoculated. In 

 this way the spore-free organisms are killed off. Pure 

 cultures may be thus obtained, or this procedure may require 

 to be followed by the roll tube method under anaerobic 

 conditions. An inoculation experiment, if available, may 

 also be made on a guinea-pig. 



QUARTER-EVIL (GERMAN, RAUSCHBRAND ; FRENCH, CHARBON 

 SYMPTOMATIQUE). 



The characters of the bacillus need be only briefly described, as, 

 so far as is known, it never infects the human subject. The natural 

 disease, which specially occurs in certain localities, affects chiefly sheep, 

 cattle, and goats. Infection takes place by some wound of the surface, 

 and there spreads in the region around, inflammatory swelling attended 

 by bloody oedema and emphysema of the tissues. The part becomes 

 greatly swollen, and of a dark, almost black, colour. Hence the 



