402 PROTOPLASMIC ACTION AND NERVOUS ACTION 



control the polar influence is all-important/ If what is 

 true of artificial electric currents is true also of the 

 currents produced by the Kving system in its own 

 activity, the conclusion seems unavoidable that the 

 bioelectric currents exert a controlHng and co-ordinating 

 influence in normal growth processes as well as in normal 

 stimulation.^ 



Perhaps the most important general inference to be 

 drawn from such experiments is that the electric current 

 under appropriate conditions has a direct promoting 

 influence on the synthetic reactions in living matter, 

 i.e., those underlying growth and repair, as well as on 

 the reactions involving oxidation and decomposition 

 which yield the energy for normal activity. Many 

 years ago, before the development of modern physical 

 chemistry, Hering reached certain general conceptions of 

 the relation of the current to protoplasmic action 

 resembhng closely in many respects those reached as the 

 result of our present analysis.^ Hering regards the 

 bioelectric currents as essentially an index of chemical 



' In a recent paper, I have called attention to a number of analogies 

 between organic growth and the growth of precipitation-structures on 

 metals (Zn, Fe, Co, etc.) in ferricyanide solutions; control by electrical 

 conditions is also characteristic of such precipitation-growths (Biological' 

 Bulletin [1917], loc. cit.; cf. pp. 162 ff.). 



* According to Kappers, the direction of outgrowth of nerve-tracts 

 in the central nervous system is the expression of a directive electrical 

 influence (analogous to galvanotropism) which he calls "neurobiotaxis." 

 Cf. Kappers, "On Structural Laws in the Nervous System," Brain^ 

 XLIV (1921), 125, and earlier references there given. Cf. also Child's 

 discussion in his Origin and Development of the Nervous System, University 

 of Chicago Press (1921), chaps, x, xi. 



3 Hering, Lotos, IX, Prag (1888), translated in Brain, XX (1897), 

 232. 



