抄録
The electrical excitability of the eye increases temporarily after illumi-nation, and the time course of this variation is characteristic of the'wave-length of the light used for illumination. The sensibility of the eye to wave-length differences was studied with the time constant of th eleectrical excitability as the index.
For a comparison, thresholds for hue discrimination were measured over the entire range of the spectrum. The curve for just perceptible dif-ferences in wave-lengths plotted against wave-lengths shows minima in the violet, blue-green, yellow and orange.
As the time constant of the electrical excitability after illumination was chosen the crest time which means the interval between the end of illumina-tion and the maximum of excitability. The crest time increases in a characteristic manner as the wave-length λ is shortened. If the decrease of wave-length Δλ corresponding to a definite amount of increase in crest time Δτ is plotted against λ, a curve is obtained which represents a close copy of the curve for hue discrimination. This fact suggests that the physiological basis for hue discrimination lies in the periphery, as has been assumed in the theories of color vision.
