STRUCTURES RESEMBLING ORGANIC GROWTHS. 177 



electrolyte-solution, separated from medium by a thin parti- 

 tion which prevents diffusion (i. e., is semi-permeable) and can 

 undergo the chemical changes necessary for the generation of an 

 electric current, e. g., oxidation at one region simultaneously 

 with reduction at another. Under these conditions medium M 

 may be permanently of a different composition from medium E, 

 both are electrical conductors of the electrolytic kind, and local 

 chemical changes resulting in ionization or deionization within 

 the substance of the partition-film will result in corresponding 

 electrical effects which may be transmitted and produce chemical 

 effects at a distance just as in the case considered above. This 

 appears to be the type of arrangement exemplified in the living 

 cell. 



To understand how such currents may be formed without a 

 metallic conductor it is necessary to consider more closely the 

 nature of the part played by this conductor in the usual type of 

 circuit. In the above example the platinum wire serves simply 

 as a means for transmitting electricity, a positive charge passing 

 to (or a negative away from) the metal from each Cl atom and 

 from the metal to each Fe ++ ion. Electroneutrality is thus 

 preserved on either side of the interface; the only region where 

 chemical change occurs is where electricity is thus added to or 

 abstracted from the substances in contact with the electrodes. 

 This last is the essential condition of all electrolyses; obviously 

 the precise character of the chemical transformations in any 

 special instance depends on the nature of the substances present 

 at the electrodes. Extensive molecular rearrangements may 

 take place under some conditions; thus the anodic oxidation 

 may result in syntheses as well as in decompositions; similarly 

 with the reductions at the cathode. In the interior of the wire 

 no permanent change occurs, since at each region electrons are 

 simultaneously entering from the one side and leaving from the 

 other in equal quantity, leaving the local condition unaltered. 

 In the interior of the solution diffusion-changes may occur; but 

 apparently there are no interionic or intermolecular transfers of 

 electrons, since the quantity of electricity passing through the 

 circuit is strictly proportional to the number of ions reaching 

 the electrodes and charging or discharging there (Faraday's 



