The Cartesian bull's eye in the classroom.
A replication of Descartes' demonstration of the inversion of the retinal image is described. Suggestions are made for both preparing a cattle eye and constructing an artificial one for purposes of classroom demonstration.
D000818:Animals; D002417:Cattle; D008959:Models, Neurological; D012160:Retina / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*