IMMUNOLOGICAL RELATIONSHIPS 349 



offer no coiulusixe e\ idence as to ^vhether or not the inflani- 

 nialion lollo^ving tlie j^rcparation is conditioned by j^revioiis sen- 

 sitization to snbstances contained in the bacterial filtrates. 

 Although no eosinojjhiles can be detected, it is doubtful whether 

 there exist any characteristic morphologic criteria ol allergic in- 

 liannnation. 



Witebsky (1936) recently suggested the following working hy- 

 pothesis on the pathogenesis of the phenomenon of local tissue 

 reactivity: According to this author, the phenomenon may be a 

 double-phased process. The bacterial active principles injected 

 locally may be first adsorbed by the endothelial cells of blood 

 \essels, the intracellidar adsorption of the locally introduced 

 active principles being made possible by normal antibodies of 

 the cells. When the provocative injection is given intravenously, 

 the introduced material is conducted to the place Avhere the anti- 

 bodies have accumtilated. Morgenroth described a phenomenon 

 called "Ueberspringen von Amboceptoren." This means that sen- 

 sitized cells may give up some of their antibodies Avhen non- 

 sensitized cells are added. The reversibility of toxin-|-antitoxin 

 combinations are also known. The sudden appearance of ne^v 

 effective stibstances at the site of the first injection may behave 

 in the same manner as the sensitized cells in Morgenroth's ob- 

 servations. A partial dissociation of the antigen-[-normal antibody 

 complex may take place. Thus, the toxic substances first absorbed 

 and present in the netitralized phase may become liberated and 

 exert their toxic action within the cell. The lack of specificity 

 of the normal antibodies may explain the fact that a great 

 variety of stibstances may be tised for the provocative injection in 

 the phenomenon of local tissue reactivity. Attempts should be 

 made to bring experimental support to this hypothesis. 



CONSIDERATIONS OF THE MECHANISM AND NATURE 

 OF THE PHENOMENON 



In consideration of the mechanism and nature of the phenom- 

 enon of local tissue reactivity it is necessary to differentiate the 

 follo^ving phases involved in it. 



1. The special property of the bacterial active principles of the 

 phenomenon to induce a state of reactivity. 



2. Incidental infiammatory reaction which may or may not be 

 necessary for the attraction of the active principles from the blood 

 stream into the prepared site. 



