TETANUS. 167 



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 

 motile and flagellated and 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 

 point of inoculation, involving also the muscular tissues. 

 The internal organs show little change, excepting the spleen, 

 which is enlarged. The bacilli are rarely found in the blood 

 of the heart when the autopsy is performed immediately 

 after death, but they are found in limited numbers in the 

 internal viscera. If the autopsy is delayed, however, the 

 whole body of the animal becomes infected with the bacillus. 



This bacillus is grown, like ike, tetanus and other anaerobics, 

 in atmospheres of hydrogen only. 



One attack produces immunity against a second attack. 



