THE VALUE of anisocoria as a diagnostic sign has been limited by reports of normal or physiologic anisocoria in as high as 40 per cent of all patients.1Löwenstein's pupillographic method has eliminated a large number of cases of these so-called physiologic anisocorias through detailed cinematographic analysis under both static and dynamic conditions.2In order to realize the potentialities of this method, and in order to place the proper value on the finding of anisocoria, it is necessary to delimit sharply that which may be physiologic from that which is pathologic. Toward this end the present study has been undertaken. Several theories of the course of the afferent pupillary fibers have been proposed in attempts to explain various phenomena of the pupillary movements.3The most generally accepted schema is that proposed by Behr,3cwho stated the belief that the macular fibers from each retina have equal