THE PROTEOLYTIC MECHANISM IN OPERATION 85 



ever. The experience, nevertheless, is an unpleasant one for 

 both patient and physician. 



But fortunately an anaphylactic shock of this character from 

 the administration of a protein in therapeutic doses is exceed- 

 ingly rare. I have personally witnessed it only a few times in 

 the course of an experience covering the administration of thou- 

 sands of doses of proteins. Moreover, it would appear that 

 the vegetable proteins, when partially hydrolyzed, as in the prep- 

 arations of the Proteals now made in my laboratory, do not 

 produce anaphylactic reactions of this character. A possible 

 explanation of this gratifying modification will be attempted in 

 another connection. For the moment we are concerned with 

 the general theory of the anaphylactic response. 



The current interpretation of this condition is that the first 

 injection of the foreign protein has "sensitized" the tissues, so 

 that when the second injection occurs there is a sudden and mor- 

 bid reaction. Vaughan explains the condition far more plaus- 

 ibly as not due to an increased sensitiveness of the tissues, but 

 to the presence of enzymes of the antibody order induced by 

 the first inoculation. He suggests that this ferment is put forth 

 in sufficient quantities not merely to neutralize the protein that 

 called it forth, but to saturate the blood more or less ; so that 

 when the second dose of protein appears its molecules are imme- 

 diately broken up in such a way that the poison group is released 

 and enabled to act upon the tissues toxically. 



But this suggestion involves an obvious and fundamental diffi- 

 culty ; it assumes that the antibody put forth in response to a 

 foreign protein will become a menace instead of protection 

 which precisely reverses the prevalent and seemingly correct in- 

 terpretation of the character of antibodies. 



According to the view of the present writer, the rationale of 

 anaphylaxis is something quite different from this. In my view, 

 there is no question of "sensitizing" the tissues to a foreign pro- 

 tein ; inasmuch as they are inherently sensitive to all proteins, 

 foreign or otherwise, at the proper stage of disintegration. Nor 

 can I conceive that the system has developed the incongruous 

 habit of putting forth, in response to a protein invasion, anti- 

 bodies that will necessarily menace the system itself in the event 

 that the invasion is repeated. Such a phenomenon would seem- 

 ingly be an exact contradiction of the established customs of the 

 organism. 



Yet how are we to explain the anomalous fact that the organ- 

 ism was seemingly unaffected by the first dose, and yet was 

 severely poisoned by the second one, administered after an inter- 

 val of several days? 



In my original exposition of the subject, I suggested that the 



