The Discharge of Nerve Impulses From the Single Visual Sense Cell

One of the most important chemical reactions in living systems is that initiated in photoreceptive organs by light, for this photochemical activity ultimately gives rise to the nerve messages which keep the organism informed concerning one of the most significant elements of its environment. These messages, consisting of impulses in afferent nerve fibers, originate in the visual sense cells, each one of which signals the condition of illumination upon it. Upon their integration depend all the phenomena of vision. It is the purpose of this paper to describe some of the features of the activity in the nerve fiber from the visual sense cell, and to discuss briefly the peripheral mechanism whereby light energy gives rise to this activity.