ON SPECIFIC THERAPEUTICS. 89 



bound to the protoplasm molecule by certain 

 atom groupings. I am inclined to look upon 

 this as somewhat analogous to the binding of 

 the toxins and of similar proteid bodies. Yet 

 on the other hand, there are fundamental differ- 

 ences between the two. For, as I have always 

 insisted, the mode of binding the toxins is 

 peculiar in so far as it is the result of a certain 

 kind of assimilation which obviously consists in 

 processes of a more or less synthetic nature. 

 These toxin-receptors which produce immunity 

 are bodies of a more independent character, 

 and appear to be especially destined for pur- 

 poses of assimilation. This high degree of 

 independence is evidenced by the fact that, in 

 conformity with my side-chain theory, these 

 receptors are very easily reproduced by the cell 

 in excessive numbers, and after being separated 

 from the cell, find their way into the blood. 



I have now formed the opinion that in like 

 manner a part of the chemically defined sub- 

 stances is attached to the cell by groups 

 corresponding to these receptors ; these atom 

 groupings I will distinguish from the toxin- 

 receptors by the name of " chemo-receptors." 

 This view is more particularly supported by 

 the fact before mentioned, that the atoxyl-fast 



