1. Dale, W. M., Davies, J. V., and Meredith, W. J., Brit. J. Cancer, 3, 31 (1949).
2. Holiday, E. R., Philpot, J. St. L., and Stocken, E. L. (in preparation).
3. Fisher, R. A., “Statistical Methods for Research Workers”, p. 96 (10th edit., Oliver and Boyd).
4. Patt, H. M., Tyree, E. B., Straube, R. L., and Smith, D. E., Science, 110, 213 (1949).
5. Chapman, W. H., Sipe, C. R., Eltzholtz, L. C., Cronkite, E. P., and Chambers, F. W., jun., Naval Medical Research Institute, National Naval Medical Centre, Bethesda, Ma., Project NM 006 012.08.25.