[Entoptoscopy of erythrocyte flow in choriocapillaries]

The author describes how he rediscovered the flow of erythrocytes in the choriocapillaris. If the cupped palm of the hand is held in front of one eye at a distance of about 5 to 10 cm while the gaze is fixed on a bright plain surface, the flow can be observed as soon as dark dominates in the binocular competition-this is an indispensable precondition. The low illumination, through retina, pigment epithelium and Bruch's membrane, is sufficient to illuminate the erythrocytes to the extent that their images produce lifelike engrammes in the neuroepithelium, which the cortex records.