SOME OBSERVATIONS ON THE RETINAL RESPONSES OF XENOPUS LÆVIS

¹ Department of Physiology, University of Cape Town

1. When eyes of the same size, subjected to the same treatment, are tested, the retinal action current of Xenopus is of much smaller magnitude than that of Rana.

2. The several deflections of the action current run a slower course in Xenopus than in Ranas.

3. The recovery process which is essential to the manifestation of the C component is of much more protracted duration in Xenopus as compared with Rana.

4. There are reasons for believing that the eye of Xenopus is relatively more sensitive to radiation of long wave-length as compared with that of Rana.

5. Qualitative differences are found in the response of the light-adapted Xenopus eye on illumination by light of different wave-length. Negative variation is more pronounced with violet light, and the darkening reaction consists of a positive deflection. The positive component is more pronounced with white light, and the darkening reaction consists of a negative deflection.