Key points are not available for this paper at this time.
Division on Physics and Biophysical Research, The Mayo Foundation, Rochester, Minnesota, and Professor of Biophysics and Physiological Optics The Graduate School of Medicine, University of Minnesota. *Submitted for publication March 8, 1929. *An abridgment of the material presented before the American Academy of Optometry at Chicago, Ill., December, 1928.
Charles Sheard (Wed,) studied this question.