82 AIDS TO BACTERIOLOGY 



recognised when considerable absorption of toxin has 

 occurred. Its use as a prophylactic is undoubted. 

 Even in those cases where the disease is firmly established 

 the serum is often still of service. In field ambulances, 

 etc., where surgeons systematically give prophylactic 

 injections, Bazy says the mortality is only one- third of 

 that where it is only given to suspicious cases. 



The Bacillus of Malignant (Edema. 



Morphology. B. cedematis maligni is a motile rod, 

 about 4 IJL long and Ol ^ broad, with several flagella. It 

 has a tendency to grow in long filaments. It forms 

 spores in a more or less central position, but not when in 

 filamentous form. It stains readily with the ordinary 

 dyes, but is Gram-negative. 



Culture. Distinction from the anthrax bacillus is also 

 seen on cultivation. It is a strict anaerobe, and grows at 

 room temperature. Development is accelerated by the 

 presence of 2 per cent, of glucose. Gelatin is liquefied, 

 and a foul-smelling gas is produced in both gelatin and 

 agar stab cultures. Blood-serum is liquefied, but there 

 is no visible growth on potato. 



Distribution and Pathogenesis. Malignant oedema has 

 followed subcutaneous injection of musk, and the organism 

 has been found in musk-sacs. It may follow castration 

 in the horse or parturition in cattle. The organism 

 occurs in the soil, dust, and in the human intestine. 



The bacillus may be the exciting cause of gangrene after 

 injuries, particularly when the parts are crushed or 

 lacerated and soiled with earth, and is pathogenic to 

 man, horses, pigs, sheep, guinea-pigs, rabbits, rats, mice, 

 and some birds. The readiest plan for isolation is to 

 inoculate subcutaneously a guinea-pig with garden earth. 

 On death, which may occur in twenty-four to forty-eight 

 hours, the bacillus is found in the cedematous fluid, but 

 , not, like anthrax, in the blood, except later, when it has 

 multiplied after death, when it may form filaments 15 to 

 40 jui in length. 



The gas manifested in the frothy exudation when an 

 animal is inoculated with garden earth is absent, or nearly 

 so, when the inoculation is made from a pure culture, 

 and is therefore probably due to other organisms. 



