Sensitivity of Hands to Visible Light

Abstract

RECENTLY, reports have appeared in the press of experiments demonstrating the existence of a dermal sensitivity to intensities and wave-lengths of visible light. Many of the experiments do not appear to have precluded thermal effects, and B. Konstantinov has suggested¹ that the results may be explained by the perception of reflected infra-red radiation emitted by the hand. In the experiment recorded here these effects have been reduced, and college-age subjects have been required to discriminate between black and white.