594 ANAPHYLAXIS 



and the leukocytes adhere to the vessel-walls, thus accounting for the 

 leukopenia observed after protein injection. The endothelial cells are 

 injured, and the walls of the capillaries become more readily permeable, 

 thus accounting for the local edema often seen in anaphylaxis. The 

 fine capillaries of a given area may be occluded by thrombi, thus ex- 

 plaining the necrosis characteristic of the Arthus phenomenon. The 

 irritation of the endothelial cells extends to the smooth muscle, leading 

 to vasoparalysis and the characteristic fall in blood-pressure. The 

 affinity of the endothelial cells for the protein is stimulated by the first 

 injection, and acts in a fulminating way on reinjection, thus explaining 

 the suddenness of anaphylactic shock. 



The theory, therefore, also assumes the formation of a ferment that 

 acts primarily upon the proteins of the blood, leading to the formation 

 of fibrin, which, as it were, mechanically induces the lesions and symptoms 

 of anaphylaxis. While it offers a plausible explanation, the theory is 

 not well supported, and at best may be regarded as a modification of 

 Vaughan's theory, demonstrating one way in which the protein poison 

 may act. 



THE CELLULAR THEORY OF ANAPHYLAXIS 



Many investigators have attempted to explain anaphylaxis on the 

 basis that the reaction is a cellular one, that is, that the antibody is 

 within the cell and that the antigen-antibody reaction occurs in this 

 position rather than in the blood-stream by means of free or circulating 

 antibody and antigen. According to the " cellular theory/' if the serum of 

 an immunized animal containing the anaphylactic antibody is injected 

 into a normal animal (passive anaphylaxis) and is followed by an injec- 

 tion of the antigen, an anaphylactic reaction cannot occur before the 

 elapse of sufficient time for the antibody to become anchored to cells. 

 The "humoral theory," on the other hand, assumes that the antigen 

 meets the antibody in the blood-stream and explains the time required 

 between the injection of immune serum and antigen in passive anaphy- 

 laxis as due to a failure of rapid union between antigen and antibody 

 unless qualitative relations between the two are accidentally correct. 



The early theory of Friedberger, 1 explaining anaphylaxis on the basis 

 of "sessile receptors"; the experiments of Friedberger and Girgolaff, 2 

 who passively sensitized normal animals by transplanting the thoroughly 



washed organs of a sensitized animal; the transfusion experiments of 

 i 



1 Ztsch. f. Immunitatsf., orig., 1909, 11, 208. 



2 Ztsch. f. Immunitatsf., orig., 1911, ix, 575. 



