“…(1,2) and on sulfhydryl enzymes (3-8) have shown clearly that the effectiveness of the radiation is decreased in the presence of other solutes, that is, that chemical agents can protect irradiated compounds against X-ray effects. Similar studies have been extended by other workers to such biologic material as bacteria (9, io) and small laboratory animals (9,(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23). The relative protection of these living systems against X-ray damage by the introduc-…”