1. Herrmann, G., and Desfosses, L. (1880). C.R. Acad. Sci. (Paris), 90, 1301.
2. Lone, F., Berg, J. W., and Stearns, M. W., Jr. (1960). Cancer (Philad.), 13, 907.
3. Morson, B. C. (1960). Proc. roy. Soc. Med., 53, 416.
4. Morson, B. C., and Volkstadt, H. (1963a). J. clin. Path., 16, 200.
5. Morson, B. C. (1963b). Ibid., 16, 126.