490 STUDIES IN GENERAL PHYSIOLOGY 



in a liquid conductor can also be conceived of only as an excess 

 of negative or positive ions on the surface of the solution. 

 It seems to me that OstwakTs assumption is a necessary one, 

 and, corresponding with this, I believe that when we assume 

 a distribution of electricities in a nerve-muscle preparation, 

 as shown in Fig. 138, a definite number of positive ions are 

 distributed over the surface of the right half of the prepa- 

 ration, and an equal number of negative ions over the sur- 

 face of the left half of the preparation. The lines of force 

 which go out from the spheres of the spark discharge to the 

 preparation can be imagined as the connecting lines between 

 the centers of polarized elements. These connecting lines 

 would therefore end at the surface of muscle preparations in 

 the ions. As soon as the charge disappears from the 

 spheres of the discharger, the excess of positive ions on the 

 right side of the preparation and the excess of negative ions 

 on the left side of the muscle preparation can no longer 

 remain separated, and a migration of the ions a current 

 must occur in the nerves. In this case (in consequence of 

 the semi-permeability of certain elements in the preparation ?) 

 a collection of ions must occur at certain points in the 

 preparation. The ions are converted into atoms and so 

 bring about chemical effects either directly or indirectly; 

 these chemical effects bring about the contractions which 

 we notice during the passage of the spark. 1 One can readily 

 understand in this way also why the oscillatory nature of 

 the discharge is of no importance in the physiological effects 

 produced, as the latter are dependent solely upon the migra- 

 tion of ions. If our theory is correct, it is therefore to bo 

 expected that the experiments which have been described 

 can also be made successfully, when it is possible to do away 

 with the oscillatory character of the discharge entirely. 



1 1 am now inclined to believe that no transformation of ions into atoms occurs 

 in this case, and that the mere change in the concentration of ions at the surface of 

 the semipermeable membranes suffices for the result. This harmonizes with a view 

 expressed since by Nernst. [1903] 



