Abstract
The cone- and rod-responses to various spectral lights were studied-by means of the electro-stimulation method at various parts of the human retina.
1. The cone-curves were found much higher than the rod-curves in every case.
2. The cone-curves for red light showed a maximum at 1 sec. in the central parts of the retina, but its crest began to shift toward a longer time at 30° from the fovea. It was pointed out that the shift was closely connected with the alteration of hue from red to orange.
No such shift could be observed in the curves for yellow and blue, whose maxima were always located at 1.5 and 3 sec. respectively.
3. The magnitude of the rod-response was greatest at the 20° periphery, where the population density of rods was greatest.
4. The response magnitudes of the photopic receptors were represented as a function of distance from the fovea and compared with the distribution curves for color-sensitivity by Wentworth. Agreement was not satisfactory, but the curves representing the ratio of the coneresponse to the rod-response showed more satisfactory agreement with Wentworth's color-sensitivity curves. This fact suggests that some interaction takes place between cones and rods.
Prof. K. Motokawa furnished guidance and helpful criticism, for which I express here hearty thanks.
