Colour sensations produced by ultra-violet light

The crystalline lens of the author's left eye has, as the result of an accident, been destroyed. The eye is now sensitive to ultra-violet light of quite low intensity. The sensation between 3600 and 3100 A. is blue, not violet. The sensations produced by extremely faint ultra-violet light on the dark-adapted retina are discussed; the behaviour is essentially similar to that in normal scotopic vision, the light appearing colourless and the peripheral region being more sensitive than the fovea.