(55 RALPH S. LILLIE. 



this is true, the transmission of the structure-forming or growth- 

 inhibiting influence is in both cases due to the formation of 

 electrical circuits between the influenced and the influencing 

 regions. In their morphological details and in their chemical 

 composition the structures formed are, needless to say, widely 

 different in the living system and in its inorganic model, although 

 in certain peculiarities of physico-chemical constitution 

 especially the cellular and filamentous character of the formations 

 and the part played in both by semipermeable membranes the 

 precipitation-structures and the living systems show significant 

 resemblances. A precipitation-structure of a definite chemical 

 composition even shows a certain morphological specificity, i. e. t 

 the structures formed from zinc are characteristic in their appear- 

 ance and different from those formed from iron or copper. We 

 may say that under the influence of the metal the ferricyanide 

 of the solution is transformed into structure of a definite kind. 

 And this structure, once formed, becomes the condition of for- 

 mation of other similar structure. 1 



To complete the resemblance to a growing plant-filament or 

 other proliferating living system, the structures thus formed 

 ought to be capable, after isolation, of forming more structure of 

 the same kind. This is of course not the case with the precipita- 

 tion-filaments, taken by themselves, since the connection with 

 the metal is essential ; but the difference may be regarded as due 

 mainly to incidental conditions. The growing system is in fact 

 not constituted by the filaments alone, but by the combination 

 of filaments, metal and solution; the formative process depends 

 upon the interaction of all three. Something analogous may be 

 said to be true of the growing organism; in a spore placed in a 



involving electrolysis. This is what takes place in the passage of a current between 

 a metallic surface and a solution; in this case the addition or abstraction of electric 

 charges to or from substances present at the boundary is what forms the essential 

 condition of the electrolysis there taking place. The cell-surface is similarly water- 

 insoluble, and semi-permeability is characteristic; yet it allows the passage of the 

 electric current, although with a somewhat high and variable resistance. The 

 facts of polar stimulation, polar disintegration, etc., indicate that where the 

 current enters the cell-surface it produces different chemical effects from where it 

 leaves, just as in electrolysis at metallic surfaces. 



1 Cf. the description of the mode of formation of precipitation-filaments, loc. cit., 

 pp. 143-144- 



