328 PROTEIN POISONS 



(1) Enteral, (2) parenteral. Proteins that escape enteral 

 digestion and find their way into the body must be digested 

 by the body cells. When some foreign protein, like the 

 blood serum of another animal, milk, egg-white, bacterial 

 proteins, etc., are injected into the blood or tissues they 

 must be digested. There is only one way in which this 

 can be accomplished, and that is by the cells of the body, 

 and there is only one way in which these cells can do this, 

 and that is by elaborating a specific proteolytic ferment 

 which will digest and destroy the foreign protein. 



In experimental anaphylaxis the first injection introduces 

 into the body a foreign protein. This must be digested 

 and the body cells slowly elaborate a specific proteolytic 

 ferment which slowly digests it. In doing this certain 

 body cells acquire a new function. The protein of the first 

 injection is slowly digested usually without the develop- 

 ment of recognizable effects, and consequently we conclude 

 that the animal has not been affected or had its functions 

 altered in any way. But this is a mistake. The animal 

 has been profoundly affected. It has developed a new- 

 function which it may retain quite indefinitely, and which 

 may be transmitted from mother to offspring. The foreign 

 protein is digested and its poisonous group set free, but 

 this has been done so slowly and gradually that the effects 

 have not come within the range of our powers of recog- 

 nition. After the protein of the first injection has been 

 disposed of, the new ferment in the form of a zymogen 

 continues to be formed in the cells, and on the second 

 injection after the proper interval, this zymogen is acti- 

 vated and splits up the protein so promptly and so abun- 

 dantly that the liberated poison induces the symptoms of 

 anaphylactic shock. 



The following statements formulated in 1907, in our 

 opinion, still hold good: 



1. Sensitization consists in developing in the animal a 

 specific proteolytic ferment which acts upon the protein 

 that brings it into existence, and on no other. 



