A study of the direct and indirect action of X-rays upon the tissues of the embryonic fowl

Abstract

In chick embryos incubated for 1. 6, and 17 days, after a dose of x-rays (150 or 270 e), mitosis ceases in all cases. It begins again in the 1-day chick, but the older embryos die. Tissue cultures made from an irradiated 6-day chick-grow if removed soon after exposure, but do not grow if removed 24 hrs. after, indicating that death is due to an indirect action of the rays. This is related to cell metabolism since the injurious action is retarded by low temp. The lethal effect of the rays is not due to formation of stable toxic products, but probably to absence of gaseous exchange in the tissues when radiated in the shell.