Recent studies in sensory physiology have provided a new approach to the problem of the mechanism of sense organs. The discharge of nerve impulses in the afferent fibers from various receptors has been studied in preparations in which the activity can be limited to a single end organ and its attached nerve fiber. The more complete analysis characteristic of this approach is best exemplified in the work done on tension, touch, and pressure receptors (Adrian, '26; Adrian and Zotterman, '26 ; Bronk, '29 ; Matthews, '31 ; Adrian, Cattell, and Hoagland, '31; Adrian and Umrath, '29; Bronk and Stella, '32). In the case of these relatively simple end organs it has been possible to study the effect of various intensities of stimulation upon the nervous discharge and to investigate the processes of adaptation and fatigue. It is highly desirable to extend this method to the photoreceptor.
Within the last few years Adrian and Matthews ( '27 a, '27 b, '28) have succeeded in demonstrating the passage of impulses in the optic nerve of the eel, Conger vulgaris, upon stimulation of the retina by light. These investigations on the discharge in the entire optic nerve have yielded such valuable information regarding the mechanism of the visual process and especially regarding the synaptic factors that the possibility of National Research Fellow in the Biological Sciences. 'Designed aiid built by Mr. A. J. Rawson.