152 TETANUS, MALIGNANT (EDEMA, ETC. 



MALIGNANT (EDEMA. 

 The Bacillus of Malignant (Edema. 



History. Malignant oedema is caused by a very malignant 

 bacillus, discovered by Pasteur, studied by Koch and Kitt, and 

 found in the soil of gardens and in the dust of streets, which, 

 when inoculated into animals, rapidly produces the disease. 



Morphology. Rods from 3 to 5 mikronsin length and 1.10 

 mikron in thickness. They occur singly or in pairs in cult- 

 ures, rarely forming threads. The ends are square in appo- 

 sition when two bacilli come together, but rounded when the 

 bacilli are single or at the free ends of united bacilli. 



This bacillus stains with all the ordinary methods of stain- 

 ing, but does not stain by Gram's method. 



It forms spores, situated at or near the centre of the ba- 

 cillus, causing a swelling of the bacterium. (Plate III.) 



Biologic Characters. The bacillus of malignant oedema is 

 an obligate anaerobic, and does not grow at all in the presence 

 of oxygen. It grows in all culture-media in hydrogen gas, 

 liquefies gelatin, and rapidly liquefies blood-serum. 



In gelatin and bouillon it grows at the bottom of the tube, 

 and in the liquid gelatin the colonies are in the form of 

 spheres, which are scarcely discernible at first, but which, on 

 account of the fermentation developed by the bacilli causing 

 clouding of the medium, become more and more apparent. 



On agar plates in a hydrogen atmosphere it grows as whit- 

 ish bodies, which under the magnifying glass are seen to 

 consist of branching and interlacing lines radiating irregu- 

 larly from the centre to the periphery. 



The colonies grow at ordinary temperature, but best at 

 37 C. 



Pathogenesis. Men, horses, calves, dogs, sheep, chickens, 

 pigeons, rabbits, guinea-pigs, are all susceptible to the 

 disease. 



Inoculation of animals is performed subcutaneously by in- 

 troducing a small particle of the suspected material or culture 

 into a deep pocket. The symptoms developed in animals are 

 a rapid and extensive oedema, with bloody effusions at the 



