566 ANAPHYLAXIS IN KELATION TO INFECTION AND IMMUNITY 



produced. It would appear, therefore, that when the antibodies are 

 produced for a given infectious agent, then the severity of the disease 

 becomes apparent; that the lesions and symptoms are due not only to 

 the infecting microorganism and its products, but to the results of their 

 destruction. An invading army may do some pillaging, but the greatest 

 injury is done when the defenders begin the attack, the resulting fire 

 and destruction doing more harm than the invaders themselves. 



While Vaughan and his coworkers were studying the protein poison 

 in vitro, and Friedberger was investigating it in vivo, the former and then 

 the latter aiming to show that the poison liberated from the protein 

 molecule through the action of specific ferments is responsible for the 

 lesions and symptoms of disease, von Pirquet was studying the question 

 from the clinical aspect, formulating a working hypothesis on the nature 

 of infection and immunity based upon the principles of anaphylaxis, a 

 theory that has been supported by experimental data and has thrown a 

 new light upon the nature and mechanism of these processes. 



RELATION OF ANAPHYLAXIS TO INFECTIOUS DISEASES 

 Although we may not be in general accord regarding the mechanism 

 of anaphylaxis, there is, however, general agreement as regards the nature 

 of the anaphylatoxin responsible for the lesions and symptoms of ana- 

 phylactic intoxication, namely, that it is a protein cleavage product. 

 In other words, a foreign protein and, indeed, the misplaced protein of 

 our own body-cells, may be disrupted or digested by an antibody, and 

 liberate or generate a poison that, being derived from protein, is known 

 as the protein poison. In the chapter on Infection it was stated that 

 Vaughan and his collaborators regard this protein poison as the same 

 for all proteins, and as responsible for all infectious diseases, the par- 

 ticular lesions and symptoms of each disease being dependent upon the 

 site of the infection and, accordingly, upon the location of the protein 

 poison. Similarly, in the preceding chapter we asserted that anaphy- 

 laxis is ascribed to an exactly similar phenomenon, namely, the splitting 

 of the foreign protein by an antibody (ferment) and the liberation of a 

 protein poison. In studying serum sickness, an anaphylactic phenom- 

 enon frequently observed in man following the administration of horse 

 serum, von Pirquet argued that the period of from eight to ten days 

 usually following the injection before the appearance of symptoms was 

 the time required for the production of the antibody, which then re- 

 acted upon the serum still remaining in the body-cells and fluids, and 



