[Germ cell population of chick embryos incubated 5 1/2 days after ultraviolet irradiation of young blastoderms]

Chick blastoderms, incubated for 5 hrs., were wholly irradiated with ultraviolet light (2 537 A). With ultraviolet doses of 14,400 and 16,200 erg/mm2, the embryos, ofter morphologically abnormal, which developed from these blastoderms, were shown to contain, at 5 1/2 days of incubation, very few or no germ cells in the region of their primordia.