1 82 RALPH S. LILLIE. 



condition of the surface-film, induced (e. g.) by external agents, 

 may also produce bioelectric circuits accompanied by oxidation 

 processes; thus a region of increased permeability resulting 

 from stimulation may be the condition disturbing the equilib- 

 rium; or a local metabolic change may take place in the surface 

 film resulting in abstraction of cations from the cell-interior by a 

 process of reduction; in a circuit like that imagined above such 

 a change would result in oxidation at other regions of the cell- 

 surface. The conditions under which local oxidations occur 

 and bioelectric circuits originate undoubtedly vary widely in 

 different cells, and probably also in the same cell at different 

 times. 



It thus seems clear that electrical circuits may originate 

 through chemical reactions which take place at the boundary 

 between solutions of different composition separated from each 

 other by semi-permeable partitions having the properties of the 

 plasma-membranes of living cells. There is no theoretical neces- 

 sity for a conductor of the first class. Local transfers of elec- 

 tricity to and from the protoplasm may occur simultaneously 

 at two different regions of the cell-surface as the result of chemical 

 interaction between the substance of the surface-film and ions 

 or ion-yielding substances present in the protoplasm or in the 

 medium; circuits between these regions thus arise. The possi- 

 bility of this general condition must be admitted if we accept the 

 general electrochemical theory that the metallic conductor in 

 (e. g.) an oxidation-reduction cell enables the reaction to take 

 place simply by serving as medium for the transmission of elec- 

 trical charges. The phenomenon of chemical action at a distance 

 appears indeed to be a clear demonstration that chemical action 

 depends upon the transfer of such charges. The production of 

 the bioelectric circuits becomes intelligible if we assume that the 

 charges conditioning the reactions at the electromotor surfaces 

 may be derived from oxidizing or reducing substances present 

 in the protoplasm, or surroundings, just as readily as from a 

 metallic conductor. 



This general conception is evidently related to the conception 

 of ionic exchange in such a phenomenon as absorption. 1 Local 



1 See Hober's "Physikalische Chemie der Zelle," pp. 238 seq. 



