TUBERCULIN REACTION 623 



than sensitization to typhoid protein, which is apparently less lasting 

 and less specific than the true immunity to this infection. 



The experiments of my associates and I 1 in this field have been 

 largely tests in vitro for various antibodies, as agglutinins, bacteriolysins, 

 and complement-fixing substances in the fresh sterile blood sera of 

 persons and lower animals hypersensitive to various proteins (typhoid, 

 syphilis, diphtheria, and canine distemper), and have shown that the 

 state of hypersensitiveness to a particular bacterial protein bears no 

 relation to the presence or absence of demonstrable amounts of these 

 antibodies. The experiments of Meyer 2 have corroborated our results 

 and conclusions, and have furthermore shown that a positive typhoidin 

 skin reaction in a rabbit does not indicate the presence of resistance 

 to an infection with Bacillus typhosus. 



The sum total of these studies indicate that although antibodies 

 that may be regarded as possessing protective and curative properties 

 toward a certain protein may be present in the body fluids of persons 

 and animals hypersensitive to this particular protein, the condition of 

 hypersensitiveness in itself is no direct evidence of their presence of 

 resistance to a particular infection, although these antibodies are most 

 likely to be present in the body fluids of those persons who are hyper- 

 sensitive. The positive anaphylactic skin test is, therefore, evidence 

 of infection or sensitization to a particular protein probably without 

 bearing any direct relation to resistance to infection or reinfection. 



TUBERCULIN REACTION 



An account of Koch's discovery of tuberculin, in 1891, is given in 

 the chapter on Tuberculin Therapy. Suffice it to say here that Koch 

 was most interested in the curative properties of tuberculin, and while 

 he has accurately and clearly described the classic picture of the syste- 

 matic tuberculin reaction,he failed to apprec iate the true significance of the 

 reaction at the site of injection, although its occurrence is carefully noted. 



The Tuberculin Reaction. The reaction to tuberculin is character- 

 ized by three essential features: 



1. A constitutional reaction, consisting of fever and the accompany- 

 ing general symptoms of lassitude, anorexia, and rapid pulse, varying 

 in severity with the intensity of the reaction. 



2. A local reaction at the site of administration, varying in intensity 

 from slight tenderness and redness to severe inflammation with adenitis. 



3. A focal reaction about the tuberculous lesion. 



1 Jour. Immunology, 1916, 1, 409; ibid., 1916, 1, 429; ibid., 1916, 1, 443; ibid., 

 1916, 1, 571. 



2 Jour. Infect. Dis., 1917, xx, 424. 



