IMMUNITY AND ANAPHYLAXIS 219 



Natural anaphylaxis depends on 



a. Species of animal, e.g., cholera in man ; anthrax 



in cattle ; glanders in horses. 



b. Age, e.g., diphtheria in children ; erysipelas in 



elderly individuals. 



c. Individual, e.g., to white of egg, blood serum even 



by ingestion. (" One man's food is another 

 man's poison.") 



Acquired anaphylaxis depends on 



a. An attack of the disease, e.g., erysipelas and 



diphtheria. 



b. The injection of dead cells, e.g., tuberculin. 



c. The injection of nitrogenous matter, e.g., blood 



serum and white of egg. 



The subject of anaphylaxis has been dealt with here 

 because of its intrinsic importance, and because it would 

 seem to demand a restatement, in the near future, of the 

 philosophy not only of infection but of medicine generally. 

 The old idea of " diathesis " acquires anew its importance 

 (having received direct experimental proof), and many 

 apparently worn-out theories and old-fashioned explana- 

 tions of disease may have new life put into them. 



