3i8 PROTOPLASMIC ACTION AND NERVOUS ACTION 



and zinc, in direct contact with each other, is separated 

 from the next pair in the series by disks of cloth or paper 

 soaked with electrolyte solution. Similarly the inner- 

 vated and non-innervated surfaces of two adjacent ele- 

 ments are in contact, while the two surfaces of the same 

 element are separated by the mass of internal protoplasm 

 which is modified in a characteristic manner. This ar- 

 rangement constitutes strong evidence in favor of the 

 theory that the surface-films or plasma membranes of 

 these cellular elements play essentially the same part as 

 the electrodes or metallic plates in batteries.^ In the ac- 

 tive electric organ the current of the discharge (positive 

 stream) runs within each cell or element from the inner- 

 vated to the non-innervated surface, just as in the usual 

 type of bioelectric circuit (e.g., of a single muscle cell) the 

 intracellular direction of the current is from active to inac- 

 tive (i.e., in the external medium from inactive or ''posi- 

 tive" to active or '^negative"). Although the E.M.F. of 

 each cellular element is small, apparently the same as that 

 of a single muscle cell (viz., 0.04-0.05 volt), a high poten- 

 tial between the terminals of the series is attained by 

 means of the summation of many elements. Briinings has 

 shown that by arranging several frogs' muscles in series, 

 with the cut surface of one apposed to the uninjured 

 surface of the next, a summation of potentials may be 

 obtained.^ The structure of the electric organ is thus 

 in striking conformity with the theory that the bioelectric 

 currents originate in a manner essentially similar to that 



^ Compare Bernstein's account in his Elektrobiologie, chap, vi, p. 121. 



* Brunings, Arch. ges. Physiol., XCVIII (1903), 241. According to 

 Briinings, potentials of a volt or more can be obtained by arranging 

 muscles in series. 



