An automatic procedure is described for inter-mittent and indirect recording of the corneo-retinal potential in animals where the eye is passively moved and only the potential difference between 2 eye positions is measured after DC amplification. The potential in the 1 st position is electronically returned to a preselected level to ensure a constant baseline. Eye movements are repeated every 10 sec. Stable recordings can be obtained over several hours of experimentation. The technique is illustrated with recordings from experiments on rabbits and dogs. A light stimulus evokes an increase in the corneo-retinal potential of rabbits, which subsides after about 33 min. A slow oscillation of the corneo-retinal potential in rabbits can be brought into synchrony with repeated light-dark phases of about 20 min. each. The slow oscillation of dogs resonates with light and dark phases of about 7.5 min. each. A fast oscillation is found with light and dark phases of 1.1 min. each, both in rabbits and in dogs. Urethane intravenously injected increases the corneo-retinal potential and reduces the amplitude of the slow oscillation. The fast oscillation is not affected by urethane. The light induced changes of the indirectly measured corneo-retinal potential in rabbits and dogs are comparable to changes observed with direct recording in animals, and to changes known from indirect measurements of the corneo-retinal potential in man.