THE VARIATION OF ELECTRICAL RESISTANCE WITH APPLIED POTENTIAL : II. THIN COLLODION FILMS

The resistance of very thin collodion membranes to direct current bears some resemblance to that of living cells since it varies with the applied potential. With membranes separating two different solutions the resistance varies with the direction (and the voltage) of the applied potential, rising when less mobile ions are carried across the membrane and falling when more mobile ones are so carried. (With some membranes the resistance varies with potential when the same solution is on both sides.) These changes are very prompt and regular. There is a hysteretic effect of previous current flow. But the membranes differ from Valonia cells in that the rise of resistance is largely ohmic, there being little or no polarization potential.