Anaphylaxis and Immunity. 



89 



phenomena of anaphylaxis and of immunity depends upon a third 

 fact. It can be shown that a uterine preparation which has been 

 partially desensitized by the addition of antigen is in a refractory, 

 or "anti-anaphylactic" condition. Such a uterus no longer re- 

 sponds to the minute quantities of antigen which were at first 

 effective, but can only be stimulated by relatively enormous 

 amounts of antigen. This shows that the previous addition of 

 antigen markedly lowers the reactivity of the antibody in the 

 cells of the body. This is illustrated in Fig. 3. 



Horse Serum Washed -j> Horse Serum Washed ^ Horse Serum 



O.OI C.C. II. 21 O.OI C.C. II. 31 0.2 C.C. 



11. 14 11.23 11.26 H-37 11-40 



Fig. 3. Guinea-pig actively sensitized against horse serum November 21. Killed 

 December 12, and uterine tracing taken. After preliminary additions of antigen, 

 the organ responds only to large amounts of the latter. 



The conclusion is therefore drawn that the resistance of im- 

 munized and of desensitized animals is in very great measure due 

 to the presence of antigen in the cells, which markedly lowers 

 the reactivity of the antibody in these cells. In course of time, 

 by a spontaneous process of reaction, the antigen in the cells is 

 destroyed, and the antibody again exists alone, or in preponderat- 

 ing amount, and the anaphylactic state recurs. In a previous 

 paper I have shown that very large amounts of antibodies in the 

 serum protect a guinea-pig only poorly against anaphylactic shock. 

 The protective value of the antibodies in the blood of an animal 



