CHAPTER V. 

 IMMUNITY AND ANAPHYLAXIS. 



IF we analyze the total of studies accumulated to the 

 present time on immunity and anaphylaxis we may isolate 

 a certain number of facts which we will review as briefly 

 as possible with the interpretations which have been given 

 them. But first let us see if it is possible to separate from 

 the total facts a general idea which will explain the nature 

 and the mechanism of the reactions which determine the 

 different phases of evolution of the infectious diseases and 

 of the various pathologic states no matter whether these 

 states are caused by animal or vegetable albumins con- 

 sidered as normally toxic, such as venins, the serum of 

 eels and turtles, ricin, abrin, etc. ; by synthetic colloids such 

 as the arsenobenzenes; or, finally, by albumins considered 

 as exclusively nutritious when they penetrate into the internal 

 substance of the organism by the intestines after complete 

 digestion, but which provoke anaphylactic states when 

 made to penetrate into this interior by subcutaneous, intra- 

 venous or even intrarectal injections. 



We have not failed to notice how difficult it is to define the 

 limits between the different groups of substances just enum- 

 erated. Thus, a certain number of toxic albumins or of 

 pathogenic bacteria may be absorbed by mouth without 

 causing symptoms, others remain pathogenic after having 

 undergone gastric and intestinal digestion. All possess a 

 certain number of characteristics in common and the value 

 of these characteristics for any classification whatever 

 will always furnish material for endless discussions. It is 

 necessary to note that the distinctions indicated above and 

 now made again have no absolute value and that they 

 are made only provisionally for the clarity of the discussion 

 which follows. 



