240 MICROBES AND TOXINS 



seem, a sort of general anaphylaxis in addition to the 

 specific form of anaphylaxis. Richet is inclined to consider 

 that in the phenomena of anaphylaxis there is in reality only 

 a relative specificity, and that the apotoxin is a poison without 

 any specificity which attacks and paralyses the central nervous 

 system, affecting in this particularly the vasomotor centres. 

 " It seems to me very probable that in the study of the whole 

 field of the different forms of anaphylaxis produced by different 

 substances a great analogy if not identity would be discovered 

 in the symptoms of all forms of anaphylaxis, so that we may be 

 permitted to believe in the general analogy if not in the identity 

 of all the different apotoxins, the various anaphylactic poisons. 

 There would thus be a very simple conclusion, namely, that 

 there is one poison and one only, the apotoxin produced in 

 all the forms of anaphylaxis." 



Richet's poisons produce in the body, besides anaphylaxis, 

 immunity. With mytilocongestin the anaphylaxis disappears 

 after about six weeks and the immunity persists. Ana- 

 phylaxis thus gives place to its opposite "prophylaxis'' and 

 toxogenin to antitoxin. The two conditions " develop side by 

 side from the moment of the first injection. Hence it is 

 necessary to distinguish closely between the immediate and the 

 late effects. During the anaphylactic period there is a striking 

 supersensitiveness as regards the immediate symptoms, but 

 there is already some immunity towards the late effects of the 

 poison. If the animal survives the immediate effects of the 

 second dose, it presents no further symptoms during the days 

 following.!. . . Anaphylaxis is the first stage in prophylaxis'' 

 These views recall those of Behring. " However para- 

 doxical it may seem, there can be no doubt that horses which 

 have become strongly immune as the result of treatment with 

 tetanus toxin yet possess a histogenic supersensitiveness of 

 their tissues towards the tetanus toxin." These properties are 



' Richet applies the same idea to serum-anaphylaxis and to anaphylaxis 

 in general. ' ' The anaphylactic reaction is a defensive function and is 

 destined to maintain intact the chemical constitution and homology of 

 each animal species by preventing foreign albumins from entering the 

 protoplasm of the cells so as to modify their specific chemical structure." 



