PART IV 



CHAPTER XXVIII 



ANAPHYLAXIS IN ITS RELATION TO INFECTION AND 



IMMUNITY 



IN reviewing our knowledge of the nature and mechanism of anaphy- 

 laxis we found that ordinarily innocent substances, such as sterile normal 

 serum and egg-albumen, when injected into animals, may give rise to 

 severe and even fatal intoxication, not because these substances are 

 poisonous in themselves, but because the antibodies which they stimu- 

 late the body-cells to produce react with the innocent protein in the 

 body fluids or cells or both producing the phenomenon called anaphy- 

 laxis. Here, indeed, we have an example of antibodies apparently 

 injuring our body-cells instead of protecting them. And now the ques- 

 tion very naturally arises, are the lesions of the many diseases caused 

 in a similar manner, the antibodies acting with the bacterial cell and 

 producing the anaphylactic state? In view of the fact that they may do 

 actual harm, in some instances at least, are antibodies really protective 

 and beneficial, and if so, in what manner? 



It is not my purpose to review here the general subjects of infection 

 and immunity, but to discuss briefly the intimate connection of what 

 we call anaphylaxis or allergy with infection, and to show that anaphy- 

 laxis may be the first step in the process of immunity; indeed, that well- 

 marked antibacterial immunity may be an example of an early and 

 efficient "anaphylactic" reaction. In other words, while the striking 

 and severe symptoms of serum anaphylaxis in either man or lower 

 animals give us the impression that we are here dealing with some new, 

 distinct, and strange phenomenon, these may be, in fact, but exaggerated 

 and severe examples, largely dependent upon quantitative factors of 

 what occurs during each infection. More than this, in the terms of the 

 humoral theory of anaphylaxis these symptoms may be due in part 

 to the action of a poison formed or released through the destruction of 

 the antigen by the antibody; the antibody being, therefore, apparently 

 imperfect in its action, as it does not neutralize the protein poison. 

 Taking, as an example, a substance, such as sterile horse serum, while 



ordinarily harmless itself, bad effects may follow its injection at once 



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