FIRST STUDIES ON ANAPHYLAXIS 13 



days, the guinea-pig reacts but very little or not at 

 all. In this latter case it remains for some time un- 

 affected by every fresh injection of serum, even if 

 made after the expiration of twelve days. In other 

 words, after having received by the peritoneal route 

 a massive dose of serum before the establishment of 

 the anaphylactic state, the animal remains immune 

 for some time. 



Such was the exact state of our knowledge at the 

 time of the appearance of our first two published 

 memoirs on anaphylaxis and anti-anaphylaxis, written 

 in collaboration with E. Steinhardt.* 



In order to obtain a clue to the solution of the facts 

 we have just summarised — facts which at the time 

 appeared both without parallel and incomprehensible, 

 because they were altogether outside the province of 

 known phenomena — we put the question to our- 

 selves from the ou^et as to whether the sensitised 

 guinea-pig, though apparently in the enjoyment of 

 excellent health, had not in reality some latent 

 lesion of the nervous system. Perhaps, we reflected, 

 a second injection, made ten to twelve days after the 

 first, might call into activity such nervous lesion, 

 and this would have the effect of developing those 

 grave complications which result in death. 



This hypothesis shews to what point we had ad- 

 vanced into the unknown; indeed, we were in such a 

 state of confusion that progress was impossible save 

 by feeling our way. 



Starting from the hypothesis we have just stated, 

 we decided to make the second injection of serum, 

 not intraperitoneally or subcutaneously as our pre- 

 decessors had done, but directly into the brain. By 

 thus getting into direct contact with the sensitive cell 



^ " De I'anaphylaxie et de I'anti-anaphylaxie, vis-a-vis dn 

 serum de cheval," Annales de I'Institut Pasteur, 1907, xxi., p. 117; 

 " Du mecanisme de I'anti-anaphylaxie," ibid,y 1907, xxi., p. 384. 



