THE SPLIT PRODUCTS OF TUBERCLE BACILLUS 167 



the alcoholic precipitate we have designated as the final 

 filtrate. 



The Effect of the Cellular Substance on Animals. It must 

 be borne in mind that the cellular substance with which 

 we are now dealing is that of a tubercle bacillus that is 

 avirulent to rabbits and guinea-pigs and that it has been 

 thoroughly extracted with alcohol and ether. There remains, 

 as it were, only the protein skeleton of the bacillus. 



We have injected into the abdominal cavities of twenty- 

 four guinea-pigs single doses, varying in amount from 5 

 to 200 nig. of the cellular substance, and from these experi- 

 ments we make the following statements: 



1. In no case was death caused directly by the injection. 

 One pig that received 20 mg. was found dead six days 

 later. There were several caseous nodules in the omentum 

 and one on the under surface of the liver. Microscopic 

 examination showed that these consisted of masses of 

 leukocytes and the debris of the injected bacilli. Another 

 that received 5 mg. was found dead nine days later, but 

 careful search failed to reveal any traces or effect of the 

 injection. Animals that received from 100 to 200 mg. 

 remain apparently well four months after the injection. 



2. It gives in guinea-pigs no immunity to a subsequent 

 inoculation with a virulent bacillus. Six pigs that had 

 received single intra-abdominal injections of the cellular 

 substance in amounts varying from 15 to 200 mg. were 

 inoculated one month later with a loop of a virulent culture 

 of bacillus tuberculosis and all developed tuberculosis and 

 died from it within from nineteen to one hundred days. 



3. It does, for a short time at least, sensitize guinea-pigs 

 to the tuberculosis bacillus. This is an interesting and, 

 in our opinion, a hopeful point. The following are illus- 

 trations of this action: Pig No. 159, weight 530 grams, 

 received, December 18, 25 mg. of the cellular substance. 

 Thirteen days later it was given intra-abdominally a large 

 loop of the avirulent culture suspended in salt solution. 

 The animal was sick within a few minutes. Within half 

 an hour it developed the first and second stages of anaphyl- 



