1. Aycock, W. L., J. Am. Med. Ass., Chicago, 1932, XCIX, 1056.
2. Aycock, W. L., & Luther, E. H., Ibid., 1928, XCI, 387.
3. Ayer, W. D., Am. J. Med. Sc., Philad., 1929, CLXXVII, 540.
4. Flexner, S., & Lewis, A., J. Am. Med Ass., Chicago, 1910, LIV, 1780.
5. Flexner, S., & Stewart, F. W., Ibid., 1928, XCI, 383.