METHODS OF DIAGNOSIS. 373 



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. It is, however, not possible to identify 

 absolutely the bacillus of malignant oedema without cultivat- 

 ing it. For purposes of separating the organism, roll tubes 

 of glucose gelatine may be made at once, and kept under 

 anaerobic conditions (p. 64). If the supposed malignant 

 oedema bacilli contain spores, the fluid should be first exposed 

 to a temperature of 80 C. for ten minutes, 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. 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 

 name "blackleg" by which the disease is sometimes known. The 

 bacillus which produces this condition is present in large numbers in 

 the affected tissues, associated with other organisms, and also occurs 

 in small numbers in the blood of internal organs. 



The bacillus morphologically closely resembles that of malignant 

 oedema. It is, however, somewhat thicker, and does not usually form 

 such long filaments. Like the latter, also, it is a strict anaerobe, and 

 its conditions of growth as regards temperature are also similar. The 



