These experiments were suggested by two personal subjective observations. The first was made rather startlingly in France over twenty years ago, following a champagne binge with a group of fellow aviators. When we left the café and started back to our billets my peripheral fields seemed to be markedly contracted, although central visual acuity appeared to be unaffected. I felt that I was looking through a pair of nonmagnifying binoculars. The second observation was made more recently. On leaving a brightly lighted cocktail party and stepping immediately into the dark, there seemed to be a definitely prolonged interval of my dark adaptation. The first of these experiments were conducted in my office, but concern as to my local reputation necessitated transfer of the work to a research laboratory. I was particularly fortunate in my choice of "guinea pigs." Most of them were young professional men of higher than average intelligence