90 EFFECTS OF IONIZING RADIATION fertile, 3 fertile ones were opened prematurely, 11 developed complete embryos but failed to hatch, and 23 live chicks were hatched, one of which had congenital perosis. The latter chick and six normal ones were sacrificed and their tissues radioanalyzed. Again, only barely detectable amounts of internally deposited activity were found. The remaining baby chicks are being raised and observed for possible long termeffects. At the present time all the chicks are growing normally and are in good health. Comparison of the fertility and hatchability data of Rongelap hens with those from domestic hens does not demonstrate anyeftect of radiation on these phenomena. 5.47 Internal Radioactive Studies in Chickens Decontamination A study was undertaken to determine the ability of both sodium EDTA and zirconium citrate (15) to increase the excretion rate of internally deposited fission products in the contaminated chickens. On the basis of previous experience, it was not expected that any appreclable decontamination could be effected at the time of this experiment (4 months following internal radioactive deposition). The excretion rates of 8 chickens with large body burdens of internal contaminants were determined for a period of + days as the base line for the study. Following this, two chickens were injected daily I. P. with 75 mg. sodium EDTA for four days; two received injections of 70 mg. of zirconium citrate (15), and two were injected with both zirconium citrate and sodium EDTA. Two chickens were kept as controls. The mean beta and gammaactivity excreted by these chickens was determined individually for each of the treatment days and for 1 day following cessation of treatment. Neither the zirconium citrate nor the sodium EDTA alone was effective in increasing the excretion rate as reflected by the beta activity measurements made. The combined administration of zirconiumcitrate and sodium EDTA, however, doubled the excretion rate of the beta co Gai activity. No detectable change in the rate of excretion of gammaactivity was noted. The excretion rate of fission products at this long period post contamination was less than 0.1 percent per 24 hours. Thus, the enhancement of the excretion rate by the combination of zirconiumcitrate and sodium EDTAdid not sig- nificantly decrease the total body burden. 5.48 Summary Studies of animals provided data on the nature and distribution of the radioisotopes in the tissues and the excreta. Over90 percent of the activity in the bodyof animals was localized in the skeleton. The pattern of deposition of the fission products in the skeleton seen in autoradiographs resembles that of the alkaline earths. Morphological changes which were observed in some of the bones maybe the result of the exposure of the animalto external radiation, although the effects of severe dietary changes and other disease cannot be ruled out. The alkaline earths Sr® and Ba’? and the rare earth group togetherconstituted 75 percent of the gross beta activity in the pig at 82 days post detonation. Thefish and clam had a much lower concentration of the alkaline and rare earths, and a body burdenconsiderably higher than that of the land animals. The internal distribution of fission products in the pig is probably representative of the distribution in humanbeings. Anestimate of the human bodyburden was derived from the data on pigs. Studies made on egg production of contaminated hens gave no evidence of any effect of radiation. The rate of production and the eggs produced were both normal. The extraordinary ability of fowl to mobilize calcium inshell formation resulted in the presence of very high activity in the shells of the first few eggs. The activity was associated withthefission products of the alkaline earth group. A_ significant amount of activity was found in the yolk, and lesser amounts in the albumen. The removal of activity from the body of chickens by egg production provides an effective natural decontamination process.