78 VACCINE AND SERUM THERAPY. 



Our knowledge concerning the effect of tuberculin on the 

 bacillus of tuberculosis and the tissues of the body in which the 

 bacillus is found, is still indefinite. Before tuberculin can be scien- 

 tifically applied as a therapeutic measure, it is necessary to deter- 

 mine the part played by the moderate reaction in the tissues and 

 what is to be accomplished by immunization with tuberculin. 



The reaction in diseased tissues following the injection of 

 tuberculin may be either mild, in which case, there is redness due 

 tohyperasmia and congestion, or it may be marked, producing 

 necrosis and sloughing of the diseased tissues. In all attempts 

 at immunization with tuberculin the mild reaction is preferred 

 because it does not lead to the liberation of tubercle bacilli as a 

 result of the necrosis of tissues, but does furnish to the lesions 

 an increased blood supply. 



The conception of the immunization accomplished by tuber- 

 culin injections differs, there being two important theories. Koch, 

 Wright and others believe that anti-body, specific to the action 

 of the tubercle bacillus, is produced. This, according to their 

 views, is accomplished through stimulation of all the defenses 

 of the body. In conformity to their views on the objects of 

 tuberculin immunization, tubercle bacilli are injected in the form 

 of "T. R." or "B. E." 



Maragliano, Sahli, Denys, Trudeau, and others adhere to the 

 toxin immunization theory, according to which tuberculin injec- 

 tions lead only to tolerance or immunization to the toxin liberated 

 by the tubercle bacillus. In accordance to this theory, old tuber- 

 culin as well as other tuberculins are injected, the doses being 

 gradually increased to the highest point of tolerance. The lesion 

 according to this theory is only secondarily effected, there being 

 no acquisition of immunity to the tubercle bacillus. 



Tuberculin treatment is usually only undertaken in tuber- 

 culosis of the glands, joints and bones, though in some clinics it 

 has also been used in pulmonary and other forms of tuberculosis. 

 Koch would limit its application to such cases as are still 

 curable that is, have not advanced too far nor are complicated 

 by other bacteria. In deciding upon cases amenable to tuber- 

 culin treatment Koch relies upon the body temperature as the indi- 

 cator. In uncomplicated and curable cases the temperature does not 

 rise much above normal. Various measures have been taken as 



