The ‘Seebeck Effect’ in a Purely Ionic System

Abstract

IN a recent discussion of the transducing mechanism responsible for thermal sensibility, it was argued that, if the free nerve-ending and the extracellular fluid surrounding it could be regarded as a thermocouple, a single sensory mechanism could account for the sensations of ‘warm’ and ‘cold’¹. A calculation of the potential difference associated with temperature gradients in homogeneous electrolytic solutions indicated that a thermoelectric effect large enough to account for the depolarization of a nerve fibre would almost certainly have to arise at the interface between the two phases of such an ionic thermocouple. Such an effect, analogous to the Seebeck effect for metallic thermocouples, has not previously been demonstrated, so far as we are aware, for purely ionic systems. The following results show that the effect exists, and is of appreciable size.