ANAPHYLAXIS 87 



well as the transformations which these substances undergo 

 in the interior of the organism that it will be possible to 

 discover why the organism is obliged to produce antibodies in 

 excess, what the role of these antibodies is and what the 

 nature of the reaction between antibodies and antigens. 



These reactions can be reduced to three different types 

 which we have treated in detail in the preceding chapter: 

 The evolution of diphtheria, of tuberculosis and of typhoid 

 fever. These types differ among themselves according to 

 the primary and secondary action of the antigen on the 

 organism and to the action of the antibody in excess on the 

 antigen. 



These differences can be reviewed in a few words: In diph- 

 theria the antigen acts directly on the tissues and the anti- 

 body in excess neutralizes the antigen without precipitating 

 it. The appearance of the antigen in excess coincides with 

 recovery. There is no anaphylaxis. 



In tuberculosis and in typhoid the antigen is not directly 

 toxic. In these cases the antigen is not an exotoxin as in 

 diphtheria, hut is the albumin of the bacterial body whose 

 pathogenic action on the organism is manifested only by the 

 appearance of antibody in excess. The antigen (bacillin) 

 forms with antibody in excess insoluble compounds. All the 

 symptoms of the disease are anaphylactic in nature. 



ANAPHYLAXIS. 



The study of the pathogenicity of infectious diseases 

 has led us irresistably through a series of logical deductions 

 drawn from exact experiments to the conception that the 

 pathologic manifestations in disease are exclusively ana- 

 phylactic in nature. 



To explain the nature, the mechanism and the basis of 

 anaphylaxis demands a knowledge of the nature of all the 

 septicemic diseases, and a general idea of all the researches 

 concerning these diseases. Let us see what this knowledge 

 includes : 



To Charles Richet, to whom belongs the credit for the 

 discovery of the biologic importance of the subject and of 



