RECEPTORS. 



201 



ber of receptors, which ordinarily are used for 

 normal metabolism, would be thrown out of func- 

 tion. Union of this nature would be equivalent 

 to an injury of the cell, and it is possible that the 

 action of toxoids is of this mild nature. 



A 



Fig. 5. Graphic representation of receptors of the first 

 order and of toxin uniting with the cell receptor, a, Cell 

 receptor ; &, toxin molecule ; c, haptophore of toxin mole- 

 cule ; d, toxophore of toxin molecule ; e, haptophore of the 

 cell receptor. From Ehrlich's "Schlussbetrachtungen," 

 Nothnagel's System of Medicine, vol. viii. This cut is not 

 to be taken as representing the actual morphology of toxins 

 or cell receptors. Nothing is known of their morphology, 

 if, indeed, they have any. The cut is intended merely to 

 represent, in a graphic manner, the supposed chemical 

 structure and mode of action of these substances. This 

 statement applies also to Figures 6 and 7. 



When toxin unites with cells there is involved 

 not only the diversion of cell receptors from their 

 customary functions, but in addition the destruc- 

 tive action of the toxin on the vital parts of the cell 



