TUBERCULOSIS 51 



every case of anaphylaxis. This fact is explained quite natu- 

 rally when we assume that toxins form with their antitoxins 

 compounds which are absolutely neutral for the organism 

 and that antitoxins in excess can neutralize not only the 

 excess of toxins which has passed into the circulation but also 

 by virtue of its mass action the toxins fixed "en surcharge" 

 by the cells. 



To summarize. By taking as a basis, the nature of the 

 infection, the nature and physicochemical as well as bio- 

 logical properties of the secretions of the diphtheria bacillus, 

 in other words, of its antigen as well as the nature and the 

 physicochemical properties of the compounds which this 

 antigen can form with its normal antibody and with the 

 antibody in excess (antitoxin), we may characterize diph- 

 theria in the following way: 



Diphtheria local, infectious disease. 



Antigen colloidal, soluble, directly toxic. Without incu- 

 bation. Affinity especially for the cells of tissues of ecto- 

 dermic origin. 



Normal antibody intracellular. Can fix the antigen "en 

 surcharge." Compounds of the antigen with antibodies are 

 soluble. 



Intracellular Reactions: 



1. Immunizing for the cells and for the organism, if the 

 quantities of antigen and antibody are equivalent or if there 

 is an excess of antibody. 



2. More or less pathogenic if there is an excess of antigen 

 and fixation of this latter by the cellular antibody "en sur- 

 charge." 



Intravascular Reactions. Neutral compounds soluble and 

 directly assimilable or eliminable provided the quantities of 

 antigen and antibody (antitoxin) are equivalent or if the 

 latter are in excess. Can never provoke anaphylactic hyper- 

 sensitiveness. 



TUBERCULOSIS. 



A type of evolution quite different is represented by 

 tuberculosis. 



Contrary to what we have seen for diphtheria toxin, the 



