

TUBERCULIN REACTION 583 



These reactions do not by any means run parallel. An intense 

 local reaction may occur, with no or but slight constitutional disturbance. 

 Not infrequently, and particularly in slight pulmonary lesions, signs 

 indicating a focal reaction may not be elicited. 



Nature of the Tuberculin Reaction. Koch believed that the tu- 

 berculin reaction was due to a summation of the effects of the injected 

 toxin and the toxic bodies formed by the tubercle bacillus within the 

 infected host. Koehler and Westphal, in 1891, suggested that, by a 

 union of the tuberculin with the products of the tubercle bacillus, a 

 third new body was formed in the tuberculous focus. Marmorek, in 

 1894, suggested that the tuberculin stimulated the tubercle bacilli to 

 secrete a fever-producing substance. 



Finally, in 1903, von Pirquet and Shick explained the reaction as 

 due to a "vital antibody reaction," and this explanation is the one most 

 generally accepted to-day. According to this conception, an antibody- 

 like substance produced by the bacilli and diffused through the tissues 

 enters into combination with the tuberculin, giving rise to the formation 

 of a toxic substance in the general circulation, as well as at the point of 

 inoculation of the tuberculin, von Pirquet's discovery of the cutaneous 

 reaction, in 1907, was a result of this theory, and served to establish a 

 further analogy between cowpox vaccination, tuberculosis, and the 

 tuberculin reaction. According to the principles laid down in the earlier 

 portion of this chapter, the tubercle bacilli are considered as stimulat- 

 ing the body-cells to produce an -antibody or a " ferment" in the nature 

 of an amboceptor, which splits the tubercle protein contained in tu- 

 berculin, liberating a protein poison, which produces a general, local, 

 and focal reaction. 



The general reaction may be explained as due to a general effect of 

 the poison on body-cells. The local reaction is caused by a concentra- 

 tion of the poison at the site of administration of the tuberculin, and the 

 focal reaction is due to the fact that cells about the lesions are more 

 sensitive to the effects of the poison than are other cells, probably because 

 they are most concerned in antibody production and are supplied with a 

 large number of sessile or attached receptors (amboceptors) for the 

 tuberculin. 



Specificity of the Tuberculin Reaction. The tuberculin reaction is 

 highly specific. This does not mean that every case of tuberculosis 

 will give a tuberculin reaction, and positive reactions are occasionally 

 found in apparently healthy persons and cattle. The conditions under 

 which a negative reaction may occur in the presence of tuberculosis 





