BIOLOGY OF CLOSTRIDIUM WELCHII 423 



weeks dropping to 428 grams when the abscess healed and the animal 

 returned to its normal healthy active condition, gaining 50 grams in 

 the next week. On March 20, forty-two days after the first inocula- 

 tion, 1.5 cc. of a fresh culture from human feces, which was pathogenic 

 for a control pig in thirty-nine hours and produced a violent reaction, 

 was injected into this pig which had completely recovered from the 

 reaction of the non-pathogenic strain. After twelve days the pig 

 succumbed having lost weight consistently going from 527 to 267 

 grams. The intestine and other organs were exposed due to the open 

 abscess extending the entire length of the abdomen with pus filling the 

 subcutaneous tissues. Immunity must have been produced to have 

 kept the pig alive for so long a time while undergoing such a severe 

 infection. 



III. A guinea-pig weighing 656 grams was inoculated subcutane- 

 ously on February 6, 1917, with 2 cc. of milk culture 6 isolated on 

 July 16, 1916. The pig lost weight and showed the typical lesions 

 with the presence of gas bubbles under the skin. After the first week 

 the abscess which had formed on the fourth day had practically healed 

 but there was another one forming near the former. The pig weighed 

 524 grams and was apparently healthy. At the end of the second 

 week the pig had completely recovered from the infection and was in 

 excellent condition. This strain although it produced a moderate 

 infection did not kill the pig. 



On March 20, 1917, another injection was given this pig, forty-two 

 days after the first. Two cubic centimeters of a very virulent strain 

 G.8 from human feces was used and proved fatal in twelve hours. If 

 any protection had been produced by the previous inoculation, it had 

 run out before forty-two days. This strain, however, was extremely 

 virulent and needed a powerful immunizing influence to counteract its 

 toxic effect. 



IV. A pig weighing 666 grams was inoculated subcutaneously on 

 February 6, with 2 cc. of milk culture 11. A characteristic lesion 

 developed in a few hours resulting in a large abscess and loss in weight 

 to 529 grams in two weeks. After the abscess broke, recovery followed 

 rapidly with the healing of the abscess. In three weeks the animal was 

 as lively as ever. On March 20, the pig weighed 578 grams and was 

 injected with 3 cc. of the same pathogen as used in III, namely, G.8, 

 which was highly pathogenic in fifteen hours in a 600-gram control 

 pig. No immunity was present here for death occurred in twenty 

 hours after severe convulsions. Again the dose was too great and 

 the interval between injections too long. 



