Some Effects of the Gamma Kays of Radium on the Developing Chick Embryo

Abstract

Chick embryos of 1-6 days'' incubation were uniformly irradiated with [gamma]-rays at an intensity 5.3 r/min. The dose given by 3 hrs. exposure (approx: 1,000 r) is near the borderline which permits the complete recovery of an irradiated embryo, with subsequent hatching and this dose is the same for all ages between 1 and 6 days. The radiosensitivity of the chick decreases regularly for the first 3 days of incubation, decreases more rapidly from 3 to 5 days and then remains fairly stationary. There is a possible differential action of roentgen rays and [gamma]-rays on the developing chick embryo.