Abstract
Influence of various colored lights upon the excitability curve for white light was investigated, and it was found that the excitability curve suffered a considerable deformation when the colored light was started immediately after the end of the pre-illuminating white light and continued until the test of electrical excitability was over. However, no such effect could be seen when the colored light was removed prior to or during the pre-illumination.
It was further elucidated that the deformation was due to selective inhibition. For example, green light inhibits chiefly the G process so tha_??_ the excitability curve for white light obtained under the inhibitory action of green light resembles that of the green-blind in whom the G process is absent. In general, colored light can inhibit the same process as it is able to elicit when it is used as the pre-illuminating light. For instance, blue light can elicit the B process, and is almost ineffective upon the other processes. Therefore blue light inhibits selectively the B process.
By taking advantage of selective inhibition the yellow process at the fovea and that outside the fovea were analysed, and it was elucidated that the yellow process at the fovea is composed of two processes R and G, whereas. the yellow process outside the fovea is an undividable single process.
