i66 



ELECTROLYTES IN BIOLOGICAL SYSTEMS 



behaves passively it should then be present in negligible quantity — at about 

 1.4 nu/m\. In the absence of an estimate of E in toad fibers, the exact nature of 

 the discrepancy remains uncertain, although it is significant that a value of E 



"T 1 



(Ajas'c 



30 60 90 120 150 180 210 240 270 300 330 360 



Fig. I. Decline of Na'^^ content of nerves in inactive Ringer's at 25° and 4°C following 

 16 hours equilibration in NaCl or Ringer's containing Na-^. Numbers in parentheses give the 

 number of experimental runs and hence the number of nerves contributing to each point. The 

 variability among nerves is shown by the vertical line at each point expressing ± the standard 

 error. 



close to that estimated for frog fibers is obtained when the potassium fluxes 

 during metabolic inhibition are introduced in equation 2. 



The source of the deviations between theories of passive ion distribution and 



