PROTEIN SENSITIZATION OR ANAPHYLAXIS 327 



antibody. According to our theory these terms are not 

 only inappropriate, but are confusing and misleading. 



The theory of Vaughan and Wheeler was first published 

 in 1907, * two years before that of Friedberger, and while 

 it has been developed and, in our opinion, confirmed by 

 later investigations, there has been no material alteration 

 in it. To one who has read this chapter thus far the essen- 

 tials of this theory must be already fairly understood, but 

 a concise statement of its fundamental points must be 

 made here even if some repetition be necessary. The 

 proteins taken into the alimentary canal are broken up 

 by the digestive ferments into non-protein split products, 

 mostly amino-acids. During or after absorption these 

 pieces are resynthesized, in part at least, to form the body 

 proteins peculiar to the species. The precipitin test shows 

 that with the exception of the proteins of the crystalline 

 lens, those of all the fluids and tissues of the body are 

 peculiar to the species. Those of one species differ from 

 those of all other species. Just where this synthesis occurs 

 in the animal body we are not sure, but that the species 

 proteins are formed from the split products of the proteins 

 of the food has been positively demonstrated. Every 

 protein molecule contains a poisonous group. In the whole 

 molecule this group is saturated with other non-poisonous 

 groups. As the whole molecule undergoes cleavage as a 

 result of enzyme action, the poisonous group is more or 

 less completely liberated, and in this process it becomes 

 activated. In alimentary digestion the poisonous group 

 becomes most active at or about the stage of the formation 

 of peptone. As the digestive process proceeds, the poison- 

 ous group is itself disrupted, and ceases to be a poison. 

 The protein poison is not readily diffusible, and for this 

 reason it is retained in the alimentary canal until it is broken 

 up and rendered inert. When an unbroken or undigested 

 protein finds its way into the blood or tissues it must be 

 digested. There are two kinds of proteolytic digestion: 



1 Jour. Infect. Dis., June, 1907. 



