IMMUNITY 37 



coagulation. Toxins may be regarded as receptors of the 

 second order thrust off by the bacteria. 



Receptors of the third order, which possess two haptophore 

 groups, one of which effects the union with the food-stuffs, 

 whereas the other lays hold on certain substances circulating 

 in the blood plasma, the complements, which cause ferment- 

 like actions cytolysins, as an example. 



The Formation of Antitoxin According to the Lateral Chain 

 Theory. The toxin molecule consists of two groups: (A) 



Fig. 6. Graphic representation of receptors of the first order and of 

 toxin uniting with the cell-receptor: a, Cell-receptor; b, toxin molecule; 

 c, haptophore of toxin molecule; d, toxophore of toxin molecule; e, hapto- 

 phore of the cell-receptor (Ehrlich). 



The haptophore or combining group, by which the toxin 

 molecule can join the receptor of the cell, and (B) the toxo- 

 phore, or poisoning group, by which means it can attack the 

 cell protoplasm after having been fixed to it by the hapto- 

 phore group. 



The effect of the toxin depends on the number of mole- 

 cules attached to the cell. A great number would bring 



