1. Cash, J. D., and Leask, E. (1965). J. clin. Path., 18, 821.
2. Hawkey, C. M., and Stafford, J. L. (1964). Ibid., 17, 175.
3. Mann, R. D. (1966). Ibid., 19, 233.
4. Nanninga, L. B., Zeller, R., and Maynes, C. (1964). J. Lab. clin. Med., 64, 706.
5. The legends to Figures 2 and 3 have been interchanged with their figures in the paper 'Electrophoresis using a constant potential across the separation field', by Dike and Bew (J. clin;Path; the January issue of the Journal