Note 19 — Chapter II

We must be cautious in assuming that such imagery is purely retinal. Scripture ('Cerebral light,' Studies from the Yale Psychological Laboratory, vol. v., 1899) argues that even the so-called 'retinal light' or 'eigenlicht' is cerebral, not retinal at all, since it is single and not double, and differs from after-images, which are displaced by pressure on eyeball. This view is perhaps too extreme in the opposite direction.