I also investigated the stability of a steady state. Figure shows how the potentials of the five Pt probes changed when these probes were first manually short-circuited for 120 s after a steady state was obtained under the application of 200 mV between the AN and CA and then separated and restored to the original state with no short-circuit. The observed potentials of the five Pt probes immediately after the removal of the short-circuit were disturbed by noise; however, they each soon (within a few seconds) returned to their original steady-state values, clearly indicating that a steady state was kept stable against fluctuation. The same results were obtained under other experimental conditions and for another electrode system with a different structure and size.