152 THEORIES CONCERNING IMMUNITY 



The results of these experiments can be summarized as 

 follows : 



1. Certain albuminoid products as such, or partially 

 digested (transformed into albumoses, propeptones, peptones) 

 which when injected in non-pathogenic doses cause the ana- 

 phylactic state (active sensitization) , are able to cause at 

 first injection a crisis similar in every way to anaphylactic 

 shock, when a strong dose is injected into the veins. 



2. The injection of a non-pathogenic dose of these prod- 

 ucts immunize in a few minutes against a fatal dose, exactly 

 as in the anti-anaphylaxis of Steinhardt and Besredka. 



We can conclude therefore that : 



The crises which follow the second injection of an antigen, 

 and the first injection of an anaphylatoxin are caused by 

 reactions of the same kind; or, in other words, the normal 

 organism is in the same state of sensitiveness to anaphyla- 

 toxins as a prepared organism is to a second dose of the 

 specific antigen. 



PHYSIOLOGICAL AND PHYSICOCHEMICAL CAUSES OF 



THE FORMATION OF ANTIBODIES IN EXCESS 



BY ANTIGENIC ACTION. 



We know now how and in what circumstances an animal 

 becomes anaphylactized; there remains to explain why 

 anaphylaxis exists, and in particular : 



1. Why heterologous albumins and biologic colloids as 

 a class are antigens. 



2. Why the process of immunization by albuminoid 

 antigens is complicated by pathologic manifestations. 



3. Why diphtheria and tetanus toxins are exceptions to 

 this general rule. 



4. Finally, why crystalloids are not antigens. 



The result of our summary of the above researches as a 

 whole is that the process of immunization consists in the 

 production by the organism of an antibody which is found in 

 excess in the blood or in the tissues of immunized animals. 



This antibody neutralizes in all cases the actual patho- 

 genic principle of the infecting agent: an organism vaccinated 



