174 APPLIED IMMUNOLOGY 



tuberculous focus unite with tuberculin by their re- 

 ceptors (Ehrlich), and the cells thus attacked pro- 

 duce receptors in excess of the demand. These over- 

 produced receptors or antibodies are then set free in 

 the serum to unite with other portions of tuberculin. 

 Thus repeated tuberculin inoculations lead to the for- 

 mation of large numbers of free agglutinins, anti- 

 tuberculin and opsonins at the point of local infection 

 as well as many fixed receptors or antibodies. 



Obviously, it will be seen that the tuberculin reac- 

 tion is dependent upon the presence of specific anti- 

 bodies. If the suspected individual is free from tuber- 

 culosis and none exists, no reaction can be produced 

 even by recourse to very large doses of tuberculin; 

 nor can a reaction be elicited in the advance stages of 

 the disease, because all antibodies have been consumed. 

 On the other hand, in the average case of tuberculous 

 infection, a comparatively small dose of tuberculin will 

 suffice to evoke a reaction. The typical tuberculin re- 

 action is threefold: general, focal and local. The 

 general reaction consists of malaise, headache, in- 

 somnia, bodily aches, nausea, cough, tachycardia, and 

 particularly a rise in temperature of one or more de- 

 grees. These phenomena are probably due to the fact 

 that tuberculin, like any other protein, is split up by 

 complement acting in conjunction with antibody, and 

 the split toxic products formed give rise to the symp- 



