TUBERCULIN THEORIES. 143 



extract of tuberculous glands. Wassermann and Bruck identified this 

 substance as tuberculin, because the sera of the treated individuals gave the 

 same positive results if a solution of old or new tuberculin was used instead 

 of the extract of tuberculous organs. Thus, the latter contained tuberculin 

 while the sera of the tuberculin-treated individuals contained amboceptors 

 designated by Wassermann and Bruck as "antituberculin." The name 

 antituberculin has not been a well chosen one, because it creates the impres- 

 sion among many as being an antitoxin. It is better to speak of it as anti- 

 tuberculin amboceptors. 



Since, according to Wassermann and Bruck these antituberculin ambo- 

 ceptors were not supposed to be formed spontaneously in tuberculous indi- 

 viduals, but only in those treated with tuberculin, their demonstration 

 could be of no apparent diagnostic value. On the other hand, their exist- 

 ence greatly furthered the understanding of Koch's tuberculin reaction, as 

 most tuberculous individuals who had antituberculin amboceptors in their 

 serum did not respond to the subcutaneous injection of tuberculin. 



Wassermann and Bruck, moreover, showed that a mixture of tuberculin 

 with an extract from tuberculous organs bound complement. From this 

 they concluded that the extract likewise contains antituberculin amboceptors. 

 Thus reasoning they developed their tuberculin theory. 



The difference in the reaction observed in a normal and tuberculous 



Tuberculin individual after inoculation of tuberculin, can be fully explained by the 



Theory of presence of antituberculin amboceptors in the tuberculous focus. By 



Wassermann virtue of their specific affinity, the amboceptors attract the injected 



and Bruck. tuberculin toward them. The tuberculin and antituberculin unite, 



and absorb the complement from the circulating blood stream, since the 



complementophile group of the amboceptor is free and unbound. By virtue of the fresh 



complement which is an actively lytic ferment, and the attracted leucocytes, a partial 



destruction and casting off of the tuberculous focus results. Upon this depends the 



therapeutic effect of the tuberculin. During a prolonged treatment with tuberculin, 



the body produces an excess of antituberculin amboceptors so that finally some appear 



free within the blood serum. When this is the case the tuberculous organism loses its 



power to react toward tuberculin, as the latter is neutralized in the blood-stream at a 



point away from the local focus. No therapeutic effect is any longer obtained from the 



tuberculin injections, so that they can, for a time, be suspended. The aim of tuberculin 



therapy should be to work with small doses so that only a focal reaction is obtained and 



the hyperproduction of antituberculin amboceptors be postponed as long as possible. 



Numerous exceptions were at once taken to this theory and its experimental data, 

 the most important of which can here be mentioned. 



Weil and Nakayama disagreed with the proof of the existence of "anti- 

 "Summier- tuberculin" in the organ extracts, on the basis that Wassermann had 

 ung's Ein- overlooked the effect of a summation of antigen. This is best explained 

 wand" (Ex- as follows: Complement is bound not only by antigen + amboceptor, 

 ception taken but also by large doses of antigen itself dependent upon the normally 

 on Ground of present amboceptors existing in_the serum employed for complement. 

 Summation of] 

 Antigen.) 



