464 PROTEIN POISONS 



The importance of sensitization as a factor in the case of 

 tuberculosis is evident in the widespread use of tuberculin 

 as a diagnostic measure. The various reactions of the 

 body to tuberculin, whether they occur as the general 

 reaction following subcutaneous injections, or as the more 

 local reaction following the vaccination of the skin with 

 tuberculin, the application of a tuberculin containing 

 ointment to the skin, or the instillation of tuberculin into 

 the conjunctival sac, are all evidences of the sensitization 

 of the body of the tuberculous individual to tuberculin. 

 Thus, when a small amount of tuberculin is injected into 

 the fluids and tissues of a normal individual, no effects are 

 noticeable, since the enzyme which causes proteolysis of 

 tuberculin is not present in the body. When, however, the 

 same amount of tuberculin is injected into the tuberculous 

 individual, it practically corresponds to a second injection 

 of this foreign protein. The enzyme present in the body of 

 the tuberculous individual attacks the tuberculin, liberating 

 the poisonous cleavage products, which in turn give rise 

 to the well-known symptom-complex designated as the 

 tuberculin reaction. In addition to the general symptoms, 

 such as fever, which accompany the presence of protein 

 poisoning within the body, poisonous proteins have a 

 decidedly irritant local effect upon the tissues w r ith which 

 they are brought directly in contact. This is seen in the 

 hyperemia and inflammation of the peritoneum in cases of 

 infection within the abdominal cavity, and is also evidenced 

 by the local reaction of inflammatory type following the 

 application of tuberculin to the mucous membrane or the 

 abraded skin of the tuberculous individual. 



Sensitization to tuberculin may be either local or general 

 in type, as is quite evident to anyone who has employed 

 the conjunctival test as a means of diagnosis in tuberculous 

 disease. This test consists in the application of a 1 per cent, 

 solution of specially prepared tuberculin to the conjunctival 

 sac. The reaction following this method of applying the 

 tuberculin test may be divided into two distinct types, 

 the first of which we may call the reaction of general sensi- 



