110 INFLUENCE OF CENTRAL NERVOUS SYSTEM 



cells. We know, moreover, nothing of the exact mechanism 

 of these reactions nor of the substances which enter into 

 them but we may assume that there is a disturbance of 

 that metabolism which regulates intracellular nutrition and 

 causes the capillary dilatation. 



What is certain, and what is important to remember, is 

 that excitations of a purely psychic order which involve 

 those highest nerve cells which determine conscious states 

 may result in functional disturbances of certain tissues or 

 organs, that is to say, in purely physicochemical reactions. 



We do not know with any certainty whether the inverse 

 is often true, whether, for example, it is possible to ward 

 off a contagion or its effects by a particular state of mind 

 but we do know that it is possible to mitigate anaphylactic 

 shock by certain narcotics as shown by the experiments of 

 Besredka inspired by E. Roux. Besredka noticed that the 

 surest method of producing anaphylactic shock in the 

 guinea-pig is to inject the antigen into the brain. At that 

 time E. Roux suggested to him the idea of anesthetizing 

 the animal before the second injection. The result was 

 as hoped for; animals narcotized by alcohol, ether, ethyl 

 chloride, urethane or chloroform, especially by the first two, 

 were rendered insusceptible to anaphylactic shock while 

 controls succumbed almost always in a few seconds or in 

 a few minutes. The first was found vaccinated against a 

 later injection (anti-anaphylaxis) . This experiment leads 

 us to a combination of very complex phenomena which it is 

 almost impossible to interpret. 



The effect produced by an antigen on a hypersensitive 

 organism depends to a certain degree, as we have seen 

 above, quite as much on the dose of the antigen injected 

 as on the rapidity with which the reactions take place. 

 For each condition of hypersensitiveness a dose of antigen 

 can be determined which will produce no apparent trouble, 

 a dose which will vaccinate and a dose which will kill. 

 However, no dose is always constant in its effect. A dose 

 which will produce violent death in an animal when quickly 

 injected within a few seconds, will become protective if 

 the injection is allowed to last a few minutes. The effect 



