1. BLOOMFIELD, S., and KELLERMAN, L. (1947). Amer. J. Ophthal., 30, 869. CoRDEs, F. C. (1937). Arch. Ophthal., Chicago, 17, 896. DowNEY, H. R. (1945). Trans. Amer. ophthal. Soc., 43, 495.
2. GRONHOLM, V. (1910). Arch. Augenheilk., 67,136.
3. HAGEN, S. (1924). Acta ophthal., Kbh., 2, 199.
4. KOLLNER, H. (1916). Arch. Augenheilk., 81, 120.
5. KOLLNER, H. (1918). Ibid, 83, 135.