PART II. 



CHAPTER X. 



EVOLUTION OF THEORIES CONCERNING 



IMMUNITY, ANAPHYLAXIS AND 



ANTI-ANAPHYLAXIS. 



INTRODUCTION. 



SINCE the origin of infectious diseases has been recognized, 

 we have tried to treat or prevent them by methods based 

 on the reactions produced in the infected organism by patho- 

 genic bacteria or by bacterial products (toxins). In this 

 research, only immediate results were considered: active 

 immunity by preventive vaccination or by bacteriotherapy, 

 or passive immunity by serum therapy. In both cases, the 

 vaccinated or recovered organism was considered normal. 

 In addition to these diseases, correctly designated as infec- 

 tious, with acute evolution (typhoid fever, cholera, plague, 

 pneumonia, etc.) or chronic (tuberculosis, syphilis, malaria, 

 etc.), there are a great number of chronic morbid states such 

 as gastro-intestinal troubles, asthma, various dermatoses, 

 rheumatisms and arthritides, neurasthenias, etc., of unknown 

 origin. 



These diseases are not contagious; we cannot assign a 

 direct bacterial origin to them. Nevertheless they present 

 many analogies in their evolution and symptoms with true 

 infections or with the consequences of such infections (tuber- 

 culosis, syphilis, diphtheria, influenza, etc.). 



Since the general use of vaccines, such as dead bacteria, 

 curative sera or certain drugs of complex composition, such 

 as the arsenobenzenes, quinine, antipyrin, chaulmoogra oil, 

 peptones; it has been found that reactions which are identical 



