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Scientific Proceedings (128) 



accepted that pellicle formation of the tubercle bacillus is an in- 

 dication of minimum wetting, the same arguments may be used 

 to explain altered pathogenicity. When the tubercle bacilli are 

 growing diffusely throughout the medium they are, according 

 to this hypothesis, wetted, and therefore when introduced into 

 the animal body are penetrated by the antibodies or bactericidal 

 substances present, and destroyed. 



Calmette 3 has recently been able to deprive the tubercle bacillus 

 of its pathogenicity by growing it in bile broth. Since bile is a 

 surface tension depressant it is reasonable to assume that its ac- 

 tion upon the growth of the tubercle bacillus is much the same 

 as that of soap. Calmette does not state whether the amount of 

 bile used in his medium caused the tubercle Lacillus to grow dif- 

 fusely through a liquid medium. We have found that when bile 

 is added to glycerine broth so that the surface tension is approxi- 

 mately 44 dynes it grows beneath the surface as it does when 

 soap is used. Growth in bile medium is more rapid and more 

 profuse than in the soap broth. We are of the opinion that the 

 attenuation of the tubercle bacillus, as observed by Calmette, is 

 due to a wetting phenomenon. 



We have also investigated the effect of sodium rescinoleate on 

 the pathogenicity of tubercle bacilli in sputum. Equal amounts 

 of T.B. sputum and 2 per cent, solution of sodium rescinoleate 

 were mixed and allowed to stand for several hours. A quantity 

 of the mixture was then injected subcutaneously into a series of 

 guinea pigs. The controls were inoculated with half the volume 

 of the untreated sputum. The animals inoculated with the soap- 

 sputum mixture developed slight enlargement of the lymph 

 glands draining the inoculated area. Fourteen days later the 

 glands had returned to normal in all the animals, none of which 

 developed further signs of tuberculosis. 



The controls all died with the characteristic picture of experi- 

 mental tuberculosis. 



The question naturally arose as to whether the sodium rescino- 

 leote had killed the tubercle bacilli or merely altered their patho- 

 genicity. This problem was attacked by placing a small frag- 

 ment of pelicle from a young culture on glycerine broth into a 



3 Calmette, A., Ann. de I'lnst. Pasteur. Par., 1921, xxxv, 561-570. 



