THE NATURE OF TOXIN 123 



DISCUSSION 



We believe with Bordet/^ Todd/^ Craw,i^ and many others 

 whose work our observations tend to confirm that hemolysins 

 are true toxins. Some toxins may not be hemolytic for the 

 reason that the toxic particle may be of a size which does not 

 readily form adsorption aggregates with red cells, or because of 

 the protective action of proteins or other emulsifying substances. 

 All antigens so far examined are hemolytic in certain colloidal 

 states. 



We have brought considerable evidence to show that the toxins 

 of C. diphtheriae and of B. megatherium probably consist of the 

 respective fat antigens of the organisms existing in definite 

 colloidal states, the particulate nature of the complexes being an 

 indispensible factor. As will be stated in greater detail in 

 another paper the particulate character of all antigens is neces- 

 sary to the colloidal concept of immune processes. Just as 

 bacteria, parasitic in the blood and tissues of an annual, are 

 colloidal particles having specific and characteristic surface 

 chemistry, so also are the artificial fat antigens which have 

 been used as substitutes for the germ bodies. The mode of 

 action of such colloids is twofold, the primary one being that of 

 ''surface," or particles, alone, the secondary one that of the 

 specific chemistry of the particles regulating the specificity of 

 the immune response. The injection of unorganized particulate 

 surface (kaolin, charcoal) leads to adsorptions and induced 

 toxicity of the plasma of the animal (anaphylaxis) ; injections of, 

 or infection by, bacteria or other cells also produce adsorptions, 

 but the character of the substances adsorbed must be different 

 for each species of cell, depending on the chemical complex 

 constituting its surface. 



The result of such adsorptions on the body fluids is a depriva- 

 tion of some of their constituents, followed by the fluids com- 

 pensating, or making good their loss by an attack upon certain 



^* Bordet-Gay, Studies in Immunity, 1909, p. 186. et seq. 



1* Loc. cit. 



16 Proc. Roy. Soc. Lond., Ser. B., 1905, 76, 179. 



