BIOELECTRIC niENOMENA 315 



potential, with associated chemical cfTects fshown in 

 the rapid breakdown and replacement of tlie surface- 

 film of oxidation-product), may occur in a three-phase 

 system of relatively simple constitution, when the third 

 phase has the form of a thin chemically alterable film 

 between the other two. 



In a chemically reactive and film-partitioned system 

 such as living protoplasm processes of a simihir kind 

 are to be expected; such processes would here also 

 necessarily be associated with variations of potential. 

 And conversely, since in all processes of this type the 

 factors controlling the formation and breakdown of the 

 hlms are mainly electrical, such systems would be 

 influenced in their chemical activity by electric currents 

 passing through them from external sources. This is in 

 fact true both for metallic systems of this type (which 

 include the mercury-peroxide system) and for li\'ing 

 protoplasm. 



In living organisms variations of electrical potential 

 are associated with physiological activities of all kinds; 

 and for detailed descriptions of the bioelectric phenomena 

 and for a review of the extensive literature reference must 

 be made to the special treatises on electrophysiology. 

 Bioelectric currents have been shown to accompany the 

 following vital processes:' automatic or reflex activity 

 of the central nervous system, rhythmical processes like 

 the heartbeat or the activity of automatic nerve cells, 

 muscular contraction, nervous and other forms of j)roto- 

 plasmic transmission, glandular secretion, stimulation of 

 special sense receptors (retinal currents), the movements 



^ For a more delailed account cf. Garten's article, "Die Produktion 

 von Elektrizitat," loc. cit., 1910. 



