Toxicity of Sulfur-35,Selenium,and Tellurium to Avian Embryos. ∗

Summary

Continuous internal irradiation of chick embryos with sulfur-35 administered on the 4th or 8th day of incubation produced abnormalities similar to those observed in selenium toxicosis of avian embryos. The highest level of sulfur-35 (1600 μc) injected into eggs containing 4-day embryos produced morphological abnormalities more severe than those produced by the same level of radiosulfur administered to 8-day embryos, or by any level of stable selenium tolerated. Selenium at levels greater than 30 μg killed all the embryos within 24 hours after injection. Nearly 20 times more tellurium than selenium was required to kill all the embryos within 24 hours; no abnormalities were observed in the tellurium-injected embryos.