582 ANAPHYLAXIS IN RELATION TO INFECTION AND IMMUNITY 



ANAPHYLACTIC OR ALLERGIC REACTIONS 



As was previously stated, if a protein, such as tubercle protein (tu- 

 berculin), syphilis protein (luetin), glanders protein (mallein), etc., is 

 concentrated and applied to the skin or mucous membrane in a local 

 area, and if the corresponding antibody or " ferment" is present in the 

 body-fluids, the protein will be digested or split and the liberated protein 

 poison and endotoxin will diffuse into the local tissues and produce a 

 local reaction, characterized chiefly by congestion and edema. This 

 local reaction, marked by paralysis of the vessel-walls with dilatation, 

 is due to the action of the protein poison on smooth muscle, and is 

 analogous to the urticarial or other eruptions accompanying general 

 serum anaphylaxis (serum disease). Since the antibody-protein reac- 

 tion is highly specific, these tests possess considerable diagnostic value. 

 The technic of application and the practical value of the more important 

 tests will now be considered. The same underlying principle governs all. 

 It would appear that these reactions should be obtained in all infections 

 where we can secure and cultivate the causative microparasite. Theo- 

 retically, this is true, although practically the problem is greatly compli- 

 cated, or indeed impossible, owing to technical difficulties and especially 

 to the fact that the protein antibody for one strain of a particular micro- 

 parasite may not be identical for all strains. 



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 appreciate 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. 



