PIGMENTS OF THE RETINA : I. THE BULL FROG.

1. The interrelations of visual purple, retinene, and vitamin A in the bull frog retina are analyzed in simple experiments, the results of which are presented in a series of automatically recorded spectra. 2. Observations are reported upon the distributions, properties, and concentrations of xanthophyll, vitamin A, and flavine in the pigmented tissues of the eye.