1. ASHTON, N. (1954). British Journal of Ophthalmology, 38, 385.
2. and COOK, C. (1953). Ibid., 37, 193. -~ (1954). Ibid., 38, 433.
3. WARD, B., and SERPELL, G. S. (1954). Ibid., 38, 397.
4. BRUCKNER, A., and FRANCESCHETTI, A. (1932). Arch. Augenheilk., 105, 1.
5. DICKENS, F. (1946). Biochem. J., 40, 145.