Summary
The experiment of Stasney et al. (6) on tumor production by the injection of chromatin fractions isolated from a rat lymphosarcoma was repeated, with two transplantable mouse lymphomas that originated and grew in genetically controlled animal strains. The development of lymphomas after subcutaneous inoculation of chromatin fractions has been confirmed, but evidence has been presented to show that the tumors which result do not possess the genetic constitution of the host in which they arise, but that of the original tumor. The most probable explanation of these findings is contamination of the chromatin fractions with surviving cells, although, as in the experiments of Stasney et al., intact cells or nuclei could not be detected microscopically in any of the fractions studied.