1. Abbott, M. E. (1927-8). Amer. Heart J., 3, 381, 392, and 574.
2. Blackford, L. M. (1926). Arch. intern. Med., 41, 702.
3. Brit;Bramwell, C.,1947
4. Bramwell, C. and Jones, A. M. (1941). Ibid., 3, 205.
5. Bayley, R. H., and Holoubek, J. E. (1940). Ibid., 2, 208.