A THEORY OF THE IMPROVED PERFORMANCE AND SURVIVAL PRODUCED BY SMALL DOSES OF RADIATIONS AND OTHER POISONS

Recent evidence of decreased disease incidence and increased expeetation of life in irradiated populations of insects, mice, and rats are reviewed. Observations on irradiated populations and controls led to the inference that the damaging effects of ionizing radiations were manifest even in the groups showing over-survival and that the improved survival resulted through mechanism independent of those causing the deleterious actions. It was observed that the variability of survival time from subgroup to subgroup is less than in the controls. It is soncluded that this decreased variability among the exposed groups is a fundamental effect of the radiation exposure and the improved mean survival is an occasional consequence of it. A theoretical discussion of this premise is presented. (C.H.)