242 RALPH S. LILLIE AND EARL N. JOHNSTON. 



characteristic peculiarities; and since the energy of any vital 

 activity resulting from electrical stimulation e. g., muscular 

 movement is derived from chemical change in the tissue, it is 

 clear that this sensitivity implies an influence of the electric 

 current upon the chemical or metabolic processes by which 

 energy is freed. These processes are mainly oxidations, and 

 the energy thus freed may be applied in chemical and structural 

 synthesis, as well as in motor or other activity. The facts of 

 electrical stimulation, inhibition, and directive control (e. g., in 

 galvanotropism) show that the chemical reactions in protoplasm 

 can be initiated, altered in rate, or suppressed by the electric 

 current; and there is much evidence that the electric currents 

 produced by living cells in their own activity exert normally a 

 controlling influence of this kind. In the two preceding papers 

 of this series I have briefly reviewed the known facts indicating 

 that the organic growth-processes both give rise to and are 

 influenced by electric currents. 1 The universal susceptibility 

 of organisms to electric stimulation is in itself indirect evidence 

 that normal growth is subject to this form of control, since 

 functional activity, which is readily initiated by the current, 

 has a profound influence on growth-processes. Bioelectric cur- 

 rents appear always to accompany normal functional activity, and 

 many of the most fundamental cell-processes, such as the trans- 

 mission of states of excitation in cells and nerve-fibres, appear to 

 be directly determined by the currents of local bioelectric circuits. 2 

 A dependence of functional activity upon bioelectric processes 

 implies a dependence of growth upon such processes, although 

 further investigation is needed before the precise nature of this 

 interconnection can be defined. 



The recent interesting work of Child and Miss Hyman 3 has 

 given further direct evidence of such an interconnection; they 

 find that the most actively growing zones in various animals, 

 especially annelids and planarians, are electrically negative to 



1 Loc. cit., p. 181; BIOL. BULL., 1918, Vol. 34, p. 85. 



2 Cf. my recent series of papers on the general physiology of protoplasmic trans- 

 mission: Amer. Journ. Physiol., 1914, Vol. 34, p. 414; 1915, Vol. 37, p. 348; 1916, 

 Vol. 41, p. 126; Science, 1918, N. S., Vol. 48, p. 51; Scientific Monthly, 1919, Vol. 8, 

 p. 456. 



3 Cf. L. H. Hyman, Science, 1918, N.S., Vol. 48, p. 518. 



