Small selected patches of retina (approximately 1 mm2) were exhaustively searched electrophysiologically to identify every brisk-transient unit present. The patches were then marked by electrolytic lesions. 2. Whole-mount preparations were made from which the distribution of alpha cells within and around the marked areas could be obtained. 3. A one-to-one correspondence could be demonstrated between brisk-transient units and alpha cells. 4. The correspondence was maintained within a patch of retina including the central area. 5. The correspondences were subject to about 10% of uncertainty attributed to technical limitations of the method.
