The effect of spaced radiation on tissue cultures in vitro

Abstract

In a paper by Canti Spear (1929) it was shown that exposure of tissue cultures to 100 mg. Radium* (element)for 2½ minutes at 0·5 cm. (platinum filter 0·5mm.) produced a fall in mitosis followed by a compensatory increase, after which mitosis became normal, fig. 1. The same paper described the variation in mitotic activity at different periods after exposure to the same radium for 9 minutes. From the data given it is possible by interpolation, to construct a “mitosis curve” for the 6 hours following an exposure of 5 minutes’ duration, fig. 2. The following experiments were made in order to study the effect of two irradiations of 2½ minutes each, separated by two different time periods.