236 PROTOPLASMIC ACTION AND NERVOUS ACTION 



related to its general influence on electrons, an influence 

 shown in the photoelectric effect. 



The phenomena of induced reactions, which are 

 almost certainly of great importance in cell-metaboHsm, 

 are probably also to be affiliated in a general way with 

 photocatalysis and electrolysis (which may perhaps 

 be called ^'electrocatalysis"); but it is impossible here 

 to do more than direct attention to these possibiH- 

 ties, the investigation of which is the subject of 

 physical chemistry rather than of biology. It is 

 sufficiently evident that all conditions influencing chemi- 

 cal reaction-velocities are of fundamental biological 

 interest. 



In considering the case of heterogeneous catalysis 

 (or chemical contact effects) and the influence of anti- 

 catalyzers, the effect of the latter on contact-potentials 

 should be noted. These potentials are affected by many 

 organic substances, especially surface-active compounds;^ 

 the strength of the current in a battery and the rate of 

 the associated chemical effects may thus be decreased. 

 For example, in the formation of precipitation-structures 

 from zinc and Fe under the influence of local circuits, 

 the presence of alcohols, esters, and other surface-active 

 compounds of the anaesthetic groups has a well-marked 

 retarding influence.^ The concentrations required for 

 pronounced retardation are similar to those effective in 

 the above-described forms of anticatalytic action, and 

 the effect may be described as anticatalytic, although 

 its conditions are probably complex, the influence on 



' Cf. the papers of Gouy, Abl, Grumbach, Loeb and Beutner cited 

 below. 



* Unpublished observations of my own in Clark University. 



