BIOLOGY OF CLOSTRIDIUM WELCHII 413 



and pancreas. Smears showed the presence of capsules and 

 Gram-positive bacilli from the serous fluid and disorganized 

 tissues upon microscopical examination. The gas bacillus seems 

 to select certain tissues and organs of the body, namely, loose 

 connective tissue, voluntary muscles and liver, perhaps on ac- 

 count of the glycogen which they contain. Gas may appear 

 in the tissues as early as eight to ten hours after inoculation. 



A larger amount of culture is necessary for infection when 

 given intraperitoneally than when given subcutaneously or 

 intravenously yet if lethal doses are used, the same effect takes 

 place in the tissues and body fluids. The lethal dose in intra- 

 peritoneal injections was 0.25 cc. for a 607-gram guinea-pig or 

 0.04 cc. for a 100-gram pig. The minimum lethal dose for 

 subcutaneous and intravenous injections was 0.1 cc. for 400 to 

 450-gram guinea-pigs. 0.1 cc. was the smallest amount that 

 could be inoculated with the needles available. 



The laboratory animal employed for the most part to test 

 the pathogenicity of Clostridium Welchii was the guinea-pig, the 

 guinea-pig being more susceptible to infection that the rabbit. 

 As far as possible pigs weighing about 500 grams were used 

 which had not been previously used for experimentation. The 

 subcutaneous injection was adopted chiefly because it proved 

 more successful than the intraperitoneal. The rabbit is more 

 resistant to local infection than is the guinea-pig but nevertheless 

 lesions can be produced by virulent cultures provided larger 

 doses are given. 



Subcutaneous inoculation of virulent cultures of Clostridium 

 Welchii when injected into a guinea-pig will produce severe local 

 infections, terminating fatally in from ten to thirty-six hours in 

 the majority of cases, the more virulent the organism the quicker 

 being the reaction. In exceptional cases, death has occurred 

 after five to nine days with the recovery of the organism from the 

 tissues at autopsy. In one case a 353-gram pig received 1 cc. 

 injection of number three milk culture and lived for eleven days, 

 having lost 140 grams and developing an abscess over the entire 

 abdominal region which gave off a strong, offensive, putrefactive 

 odor. In cases of sublethal doses or non-pathogenic cultures a 



