PHYSICO-CHEMICAL BASIS OF TRANSMISSION 409 



phase is electrolytic, the other being metallic; but the 

 chemical reaction, which is confined to the interfacial 

 layer, does not depend directly on the internal composi- 

 tion and physical properties of either phase but only 

 upon the conditions at the interface. When a current 

 of sufficient intensity passes across the boundary at any 

 region, in either system, it causes polarization and pro- 

 duces chemical effects ; and under the conditions already 

 defined, these effects may be automatically transmitted 

 over the whole surface. 



Such a conception of protoplasmic structure and 

 action is fully consistent with the views reached on the 

 basis of histological research, and it has the further 

 advantage of correlating the structural features of the 

 living system with the special peculiarities of its chemical 

 and physiological behavior. The great diversity exhib- 

 ited by living organisms shows that the protoplasmic 

 type of constitution permits the widest variation in the 

 details of structure and activity. Yet the essential or 

 fundamental structure common to all forms of protoplasm 

 is apparently uniform; viz., a film-partitioned or film- 

 bounded arrangement or organization of phases of differ- 

 ent chemical composition. With this type of structure, 

 of which an elementary model is an emulsion structure, 

 the properties of growth, chemical activity, and irrita- 

 bility characteristic of Hving matter appear to be inti- 

 mately bound up. Systems having this structure will 

 give a maximum of polarization when traversed by 

 electric currents, and hence a maximum of chemical 

 effect. Most of the problems relating to the mode of 

 action of such systems, especially the problem of the 

 conditions of specific synthesis (the most characteristic 



