234 PROTEIN POISONS 



renders the animal sensitive to the corresponding animal 

 protein, probably sufficiently protracted feeding with 

 animal proteins will likewise confer immunity. The sensi- 

 tization through feeding is specific for the protein food, 

 showing that during the processes preceding and including 

 absorption of the food protein no change takes place which 

 robs it entirely of its biological specificity. The close 

 similarity, if not identity, of the legumins of the pea and 

 vetch was shown by the interreaction of these proteins, 

 and the close relation to vignin from the pea was also 

 indicated. The near relation or probable identity of the 

 gliadins from wheat and rye was also shown." 



This is in accord with our findings of some years ago, 

 when we demonstrated that vegetable, bacterial, and animal 

 proteins contain the same poisonous group. 



The Sensitizing Group in the Protein Molecule. As has 

 been stated (Chapter V) we have split proteins into 

 poisonous and non-poisonous portions. This has been done 

 with proteins of most diverse origin, bacterial, vegetable, 

 and animal, and we have found no true protein which has 

 failed to undergo this cleavage. Certain pseudoproteins, 

 like gelatin, do not respond to this test, but all true proteins, 

 so far as tested, have been split into poisonous and non- 

 poisonous portions. This is the foundation stone of our 

 theory of protein sensitization. All true proteins are 

 sensitizers, and so far it has not been shown that sensiti- 

 zation can be established by any non-protein substance. 

 All sensitizers develop symptoms of poisoning on reinjec- 

 tion. These symptoms induced by reinjection are identical 

 in manifestation and sequence with those induced in the 

 fresh animal by the injection of the poison split off from 

 the protein molecule by chemical agents, or by the ferments 

 in the serum or organ extracts of sensitized animals. There- 

 fore, we have concluded that anaphylactic shock is due to 

 the cleavage of the molecule of the protein sensitizer on 

 reinjection, and the liberation of the protein poison, and 

 this cleavage is due to a specific proteolytic enzyme developed 

 in the cells of the animal body as a result of the first injec- 



