246 RALPH S. LILLIE AND EARL N. JOHNSTON. 



tions are surprisingly in accord with our modern physico-chemical 

 point of view. The physiological polarity in the action of the 

 current implies a polar difference in the chemical effects which 

 it produces in living matter. The closest physico-chemical 

 analogy is electrolysis; and it is to be inferred that processes of 

 the same essential nature as electrolysis underlie the chemical 

 effects of the electric current in organisms. This possibility 

 was partly recognized by the older electrophysiologists, 1 but in 

 the absence of any clear conceptions of the fundamental physico- 

 chemical constitution of living matter they could do no more 

 than make this suggestion and trust to later investigation and 

 criticism for confirmation or disproof. 



In the precipitation-structures described in this paper the new 

 structural material is also formed at the anodal regions of the 

 metal; and the inorganic growth-process at any region can be 

 accelerated by making that region more strongly anodal, or 

 inhibited by making it cathodal. The process of construction is 

 thus susceptible to electrical influence, and this influence exhibits 

 polar character a necessary consequence of its dependence on 

 electrolysis. Obviously the resemblance of the inorganic model 

 to the living system relates only to the general nature of the 

 conditions which control the chemical reactions underlying the 

 formation and deposition of structural material. The detailed 

 character of the formative processes in living matter can be made 

 clear only by further investigation, but recognition of the general 

 physico-chemical class to which the processes belong is essential 

 as a guide in this investigation. 



The senior author is responsible for Part I. of the present 

 paper. The observations and photographs contained in Part II. 

 were all made by Mr. Johnston, whose own account of his work 



now follows. 



PART II. EXPERIMENTAL. 



I. Introduction. 



It is the purpose of this paper to describe in some detail 

 various types of precipitation-structures produced by means of 

 electrolytic local action in metals, according to a method de- 



1 Cf. E. du Bois-Reymond, "Untersuchungen iiber thierische Electricitiit," 

 Vol. 2, p. 387. 



