STEREO-CHEMISTRY AND PHYSIOLOGY 477 



this way the cell extracts the necessary nutriment from bodies 

 carried past it in the blood currents. These side-chains, how- 

 ever, may serve to anchor toxin groups as well as nutritive 

 ones ; and, on Ehrlich's view, when a sufficient number of toxin 

 groups have been anchored, the nutrition of the cell may suffer 

 to such an extent that the cell dies. 



Schryver 1 has put forward a different view of what takes 

 place. A concrete example will make the matter clearer, and 

 for the sake of simplicity we may symbolise the cell by the 

 benzene tricarboxylic acid shown below : 



[2] COOH 

 [1] COOH C COOH [3] 



HC 



CH 



C 

 H 



Here the active side-chains are represented by three carboxyl 

 radicles. Now suppose that a molecule of aniline passes within 

 the range of the central carboxyl group (2), and is seized and 

 anchored by it. The presence of this large group will hinder 

 the approach of other aniline molecules to the carboxyl groups 

 (1) and (3), so that they will be temporarily put out of action 

 until the first aniline radicle is disposed of. 



We may represent the action diagrammatically in the 

 following way : 



d 



CL 



6 c a &' 



(a) Fig. 1. (6) 



1 Schryver, Chemistry of the Albumens, p. 183 (1906). 



31 



