TUBERCULOSIS 59 



Fifth, and finally, an attack of tuberculosis spontaneously 

 cured does not confer a longer immunity than a healed vac- 

 cination (Calmette, Yallee). Tuberculosis thus resembles 

 syphilis in which the possibility of a spontaneous reinfection 

 is considered as a proof of previous cure. 



In considering the total of reactions provoked in the 

 organism by the secretion of living tubercle bacilli and by 

 the digestion of these bacilli which goes on under conditions 

 which are as yet impossible for us to define in a wholly satis- 

 factory way, we can represent the evolution of spontaneous 

 tuberculous infection in the following manner: 



The bacteria which penetrate into the organism by the 

 digestive or respiratory tracts are taken into the circulation 

 and may remain there for a longer or shorter tune before 

 being fixed in the different tissues, glands and organs. A 

 certain proportion of these fixed bacteria, all the greater 

 when the bacteria are less virulent (when they secrete less 

 pure tuberculin), and vice versa are certainly digested and 

 produce a precipitating antibody which we may call anti- 

 bacillin. This function belongs properly to the bacteria 

 fixed in the organs. Those which are fixed in the tissues 

 secrete tuberculin and become the origin of infectious foci 

 and of lesions, whose evolution has been analyzed above. 

 The successive phases of the disease are thus determined 

 first by the digestion of bacteria and the production of anti- 

 bacillin, and second by the secretion of tuberculin and the 

 production of antituberculin. 



If the bacteria are less virulent the proportion of those 

 which are digested and which produce antibacillin is greater 

 than the proportion of those which are fixed in the tissues and 

 which produce the formation of antituberculin in excess. 

 On the contrary, when the bacteria are virulent it is the anti- 

 tuberculin reaction which predominates; infectious foci be- 

 come more numerous and lesions more severe. 



The experiments of Besredka, and of Manoukhine show 

 with sufficient precision the evolution of the antituberculin 

 reactions in the successive phases of tuberculosis in the 

 guinea-pig. In these very sensitive animals antituberculin 

 appears in the blood four days after the injection of the virus; 



