TUBERCULOSIS 53 



antibody in excess comparable, for example, to diphtheria 

 antitoxin in the organism. But that natural tuberculin 

 becomes pathogenic for these tissues after a longer or shorter 

 incubation and that this natural tuberculin provokes in the 

 affected organism the formation of specific antibodies in excess 

 which can be found in the blood (reaction of fixation) and in 

 the tissues (cutireaction) . 



From the fact that a true antigen can act only on a sus- 

 ceptible organism, one ought to assume that artificial and 

 natural tuberculin are two different substances since the 

 normal organism seems insensible to the action of the first 

 and on the contrary, acquires a specific sensitiveness to the 

 action of the second. 



This suggests that there is in the cells a normal antibody 

 for natural tuberculin but no normal antibody for artificial 

 tuberculin and from the point of view of specificity of antigens 

 this would be a very important point of difference. Moreover 

 we know with some certainty that artificial tuberculin pro- 

 duces on the tissues of an organism infected by tuberculosis, 

 reactions which are identical to those which natural tuber- 

 culin produces in tuberculous foci. There is then a contra- 

 diction, but a close analysis of the known facts will easily 

 demonstrate that this contradiction is only apparent. 



By studying the development of a tuberculous lesion, we 

 find, according to the researches of Besredka and others, that 

 lesions around tuberculous foci become manifest only some 

 time after the appearance in the blood of patients of the anti- 

 body in excess and a positive cutireaction shows at the same 

 time that the tissues of a tuberculous individual are impreg- 

 nated with this antibody in excess at a time when not a single 

 clinical symptom reveals the presence of a tuberculous focus. 

 The presence of antibody in excess in the blood is thus anindis- 

 pensable condition to pathogenic reaction and if this is so, we 

 may represent the evolution of the tuberculous lesion in the 

 following manner: 



The bacteria of a tuberculous focus secrete natural tuber- 

 culin of which a part is fixed by the cells of the surrounding 

 tissue while another part, "the excess," diffuses into the gen- 

 eral economy. We will see later what happens to this excess. 



