14 ANAPHYLAXIS AND ANTI-ANAPHYLAXIS 



we anticipated that anaphylactic symptoms would be 

 set up in a more rapid manner, with weaker doses 

 and with greater constancy than was the case when 

 the injections were made intraperitoneally or sub- 

 cutanebusly. 



This is, in fact, what took place : Upon introducing 

 beneath the dura mater of a sensitised guinea-pig 

 0-25 c.c. of horse serum and even less, we produced 

 in one or two minutes the same symptoms as those 

 which followed the injection of 5 c.c. into the peri- 

 toneum. Moreover, while the intraperitoneal in- 

 jections (5 c.c.) led to death in about 25 per cent, of 

 cases, those made into the brain yielded a mortality 

 of almost 100 per cent. From time to time the 

 guinea-pigs injected by the subdural route did escape 

 death, but they never failed to exhibit a group of the 

 most characteristic symptoms. 



It need scarcely be added that we took care to 

 make sure that the fresh guinea-pigs, or those pre- 

 pared with substances other than serum, tolerated 

 with impunity an intracerebral injection of 0-25 c.c. 

 horse serum. In the same way we made controls 

 with guinea-pigs sensitised to horse serum, and 

 straightway reinjected intracerebrally with 0-25 c.c. 

 of an inert fluid such as beef bouillon or physiological 

 saline solution. 



Just as in the case of the intraperitoneal test, we 

 have never noticed anaphylactic symptoms when the 

 interval of ten to twelve days between the sensitising 

 injection and the test injection into the brain has 

 not been adhered to. 



This intracerebral test not onty exhibited a theo- 

 retical interest in exploring the nervous origin of 

 anaphylactic symptoms, but it also shewed this 

 practical advantage, that it henceforth rendered 

 possible researches on anti-anaphylactic immunity. 

 Indeed, before these were undertaken it put us in 



