The CVS rabies virus, inoculated in the anterior chamber of the eye, is transported from the retina to the central nervous system only along the accessory optic tract and invades transsynaptically its terminal nuclei. On the other hand the retino-geniculo-cortical system is affected much later. Thus the virus shows a special affinity for a well defined neuronal system and behaves as a precise tracer of its intracerebral connections.