1. Lajtha, L. G., Nature, 173, 587 (1954).
2. Lajtha, L. G., Oliver, R., and Ellis, F., Brit. J. Cancer (in the press).
3. Lajtha, L. G., J. Phot. Sci. (in the press).
4. Smellie, R. M. S., McIndoe, W. M., and Davidson, J. N., Biochim. Biophys. Acta, 11, 559 (1953).
5. Payne, A. H., Kelly, L. S., Beach, G., and Jones, H. B., Cancer Research, 12, 426 (1952).