Malignant CEdema. 29 



attack. Chauveau injected 4 to 5 cc. of virulent liquid of malig- 

 nant oedema into the veins of a ram and then practised bis- 

 tournage, with the result that an invasionof malignant oedema of 

 the scrotum and tunica vaginalis followed immediately. Pure cul- 

 tures may be harmless, whilst an admixture of proteus vulgaris 

 or micrococcus prodigiosus renders them most deadly (Penzo). 

 Granulating wounds are even less favorable to invasion than 

 simple abrasions. In these the bacillus cannot enter at once into 

 the lymph channels and is exposed to destruction by the com- 

 bined influence of the air and leucocytes. 



Wounds in dropsical or gangrenous parts are equally favorable, 

 to the development of the bacillus. Under such conditions the 

 tissues are wanting in oxygen and resemble the condition of the 

 entire body after death, when the bacillus of malignant oedema 

 quickly penetrates its whole substance. Petri has traced the in- 

 fection through the genital passages of newly delivered rabbits, 

 producing a fatal metro-peritonitis and cutaneous oedenia. A 

 similar invasion may take place in other susceptible parturient 

 animals. I/Ustig in a certain number of cases satisfied himself 

 that he had traced the invasion through the intestine of the living 

 horse. Invasion by the lungs, even by spores, is usually 

 rendered impossible by reason of the presence of the inspired air. 



A large dose of the virus is most likely to effect a successful 

 invasion, since the toxins tend to debilitate and lower the de- 

 fensive powers of the tissues. and leucocytes. The effect of the 

 toxins is shown under injections into the arteries, veins or trachea. 

 A certain amount of hyperthermia follows, but there is rarely 

 any colonization and reproduction of the bacillus in the connective 

 tissue. In dogs and rabbits large doses given in this way induce 

 short inspiration and broken or double expirations. In fatal 

 doses death is preceded by extreme dyspnoea and convulsions. 

 (Rodet and Courmont). 



Lesions and Symptoms. The tissues where invasion occurs, 

 become the seat of an abundant oedematous exudation, which 

 feels boggy and painful and may even crepitate when pressed or 

 manipulated. In case of an open wound, there is a profuse 

 liquid discharge of a yellowish watery or serous aspect, and 

 bubbles of gas or froth having a somewhat foetid odor. The 

 center of the swelling may become soft and flaccid while the 



