R E T I N a L Actiox Potential -e F F E C T O F Temperature on Magnitude and Latency I N the Grasshopper

The investigation of the effect of temperature on the magnitude and latent period of the retinal action potential elicited by illuminating the compound eye of grasshoppers was undertaken for three reasons: (1) to provide additional evidence in support of the contention that the potential magnitude and latent period are controlled by cliff ercmt processes ; ( 2 ) to evaluate the effect of temperature on some of the constants in the kinetic model; and (3) to determine the validity of certain predictions suggested by the kinetic model developed in the preceding paper (Wulff, Fry, Linde, '55). The model for the potential generating mechanism postulates that the action of light on a photosensitive material produces a material designated by C which manifests itself, after the lapse of the latent period, as an e.m.f., the response niagnitucie of the retinal action potential. The material C accumulates at a rate proportional to the intensity of illumination and it is depleted, during illumination, at a rate proportional to the difference in its concentration at any time and the concentration in the dark adapted eye. This idea is formally ~*cpresented by equation 2, pagp 253. I f the depletion reaction is tliermola1)ile and the accumulation reaction is thermostable