Cornea is only innervated by free nerve endings. A corneal scarification exposes free nerve endings which are able to transport True Blue and Fast Blue dyes by retrograde axonal transport. These tracers label the perikaryon. A few days later, the rats are sacrificed and perfused with an intra cardiac 10% formaldehyde perfusion in a phosphate buffer. The analysis of ipsilateral semi lunar (trigeminal) ganglion with a Leitz Dialux fluorescence Microscope shows fluorescent blue cells. The organization of these cells in the volume of the ganglion has been determined by selective labelling of each corneotopic zone in the supero-internal quarter of the rat trigeminal ganglion. Data from the literature about the somatotopic organisation of the other parts of the rat face are in agreement with these results.