170 PROTEIN POISONS 



only the bacilli introduced by the second injection, but also 

 those remaining in the body from the first injection and 

 these together supplied enough free poison to kill. 



It will require much experimentation to show what degree 

 of sensitization can be secured by the residue, what size 

 doses should be used, and how long the condition of sensi- 

 tization continues. If men, as well as guinea-pigs, can 

 be sensitized with the residue, there is the possibility that 

 it may be of service in the treatment of initial and localized 

 tuberculosis, because it may be used to bring into existence 

 and activate a specific bacteriolytic ferment which will 

 split up and destroy the few bacilli that are in the body, 

 but we can readily see that this might be harmful rather 

 than beneficial when the number of bacilli in the body is 

 large enough to furnish a dangerous amount of the poison 

 when set free. In this case the old adage that it is not wise 

 to disturb sleeping dogs might be remembered. 



The Effect of the Precipitate Residue on Animals. This 

 is the most interesting of the split products of the tubercle 

 bacillus, and it deserves much more study than we have 

 as yet been able to give it. On healthy animals it has no 

 recognizable ill effects either in single or repeated doses, 

 large or small. We took 6 half-grown pigs and injected 

 into the abdominal cavity every third or fourth day 50 

 mg. of this residue. These injections were begun April 20 

 and continued until June 11. During this time each animal 

 received sixteen injections, a total of 800 mg. each. All 

 increased normally in weight, and five days after the last 

 injection all were killed and carefully examined and found 

 to be perfectly normal. We were led to do this because of 

 the following experience: Three sets of pigs were inocu- 

 lated intra-abdominally with the living a virulent culture. 

 These inoculations were made December 14, 1905. The 

 animals of the first set had no treatment, and when killed 

 April 11, 1906, were found to be perfectly normal. Those 

 of the second set had, December 18, 50 mg., December 22, 60 

 mg., and December 26, 70 mg. of the cell residue. All in 

 this set were killed April 11, and were also found to be 



