Derivation of the photo-electric efficiency of photoreceptors and a method of extracellular measurement of nerve current. I.

In part 1 a method is described how the nerve current iax of passively conducting nerves can be measured. iax is shown to be a quantitative measure of the receptor potential. For a known state of function of the photoreceptor iax can be used to calculate the resistance of the nerve. Part 2 is concerned with the primary electrical reaction (receptor potential) of vision. Formulae are derived which allow to calculate 1. the quantity of absorbed light (input); 2. the charge flux (output). The ratio of output to input is the photo-electric efficiency ηq. With ηq it is possible to estimate the turnover of ions and energy of the transduction reaction.