“…The significance of this observation is as yet obscure, but a similar high value for tumour cells has been recorded by Klein (1951) for several mouse tumours. On the other hand normal values for the DNA content of tumour cell nuclei have been recorded for rat hepatoma by Mark and Ris (1949), Cunningham, Griffin and Luck (1950), Price, Miller, Miller and Weber (1950), and by Davidson, Heagy and Thomson (1952, unpublished results), for mouse lymphoma by Klein (1951), and for leukemic cells in man by Davidson, Leslie and White (1951). SUMMARY. 1.…”