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ANNALS NEW YORK ACADEMY OF SCIENCES 



of several short time intervals after the beginning of the impulse. Val- 

 u s of the voltage measured at any one interval, with a given fish and a 

 given external resistance, were then averaged. As with the measure- 

 ments at the peak of the impulse, the results are conveniently shown by 

 l)l()tting the voltage against the external current. A typical set of 

 measurements is thus shown in figure 5. The points along any one 



-as 



O ampefes 0.5 



1.0 



Figure 5. Each line shows voltage vs. current at one instant, in external circuits of different 

 resistance joining electrodes on main organs of Electro jhorus. (From J. Gen. Physiol.) 



line show values of voltage and current obtained with different external 

 resistances, at the same interval after the beginning of the impulse. 

 The graph farthest to the top and right shows the measurements at the 

 peak and, thus, corresponds to the single graph shown in figure 4. The 

 other two graphs show the measurements at two later instants during 

 the impulse. 



Although a straight line cannot be drawn precisely through the 

 plotted points of the measurements at a given interval, we have been 

 unable to detect, in the series of observations, as a whole, any system- 

 atic deviation from a linear relation. It appears, therefore, that the 

 tissue can be described electrically in terms of electromotive force 

 and ohmic resistance, not only at the peak of the impulse, but at other 

 times as well. 



A simple diagram for such a description is shown in figure 6. In 

 reference to this figure, let E denote the electromotive force of the part 

 of the organs included between the electrodes at p and q, and let r de- 



