3 phocytes were considerably depressed and thatsig- nificant doses of radiation had probably beenre- ceived. In addition to the whole-body dose ofradiation and the beta irradiation of the skin, radiochemical analyses of the urine showed that measurable amountsof radioactive material had also been absorbed internally. The effects of the radia- tion can best be summarized under three headings according to the mode of exposure: penetrating irradiation, skin irradiation, and internal irradiation. PENETRATING RADIATION lower in the children <5 years of age. This degree of neutropenia wasinsufficientto result in any apparentincreased infectious processes, and, indeed, it was noted that neutrophilic leukocytosis was possible in people showing casualinfections at this time. Neutrophil levels recovered more rapidly than lymphocyte levels and reached near control levels by | year. Subseguent annualsurveys have revealed that recevery does not appear to have been complete, particularly ii n younger andolder age groups, during tt he10-yearperiod. Early platelet tounts showedless fluctuation than other blood counts andfairly consistently showed Oneofthe earliestfindings indicative of a significant exposure im these-péople was lowering of increasing depressign, reaching levels of about 30% blood. This was most marked in the 64 people on Rongelap who had received.175 rads, and wasless markedin theather groups receiving less expo- parison levels occurred during the following few weeks, Which was followed by slower recovery ody mean levels never reaching higher than 98.495 % that of the comspafison population dur- levels of leukocytes and phitelets-of the peripheral sure. The hemépoietic‘depression-4as roughly proportionat-¢o the dose in the 13% Utirikpeapl radiation’‘gceived. Even & only an esti- mated 14 rads, twas pe to distinguish slight platelet depressioniin the grouphea|whole. The that of the comparison population by the 4th week. A spurt of recovery to about 75% of com- ing th®¥0 yéars post exposure (see Figures 56 and 65). ~ Erythropotetic depression has not been a consist- ent finding as with the leukocytes and thrombocytes. Slight depression of red blood counts, periphera¥blood levets betweei?Mieveofthe high Hemf&tocrit&and hemoglobf#™has been noted at and low exposure groups. The chronological times. Bone marrow smears taken at 6 months records ofblood findings on the group exposed on showed nogross abnormalities. Smears taken at 8, Rongelap are presented in Figures 49, 50, 56, and 9, and 10 years showed an alteration in the 65 and Appendix 8, and on the Ailingnae and myeloid-erythroid ratio manifested by an inUtirik groups in Appendices 9 and 10. creased numberofred cell precursors. Depression Lymphopenia of abouthalf the level of the comof peripheral blood elements in the Ailingnae and parison Marshallese population was evident when Rongerik groups was not so pronounced as in the the people exposed on Rongelap-werefirst examRongelap group. However,a slight lag in comined ontheir arrival at Kwajalein 3 days after explete recovery in the Ailingnae peripheral blood posure (see Figures 49, 50, and 65). In children count has also been noted. The persistent depres<5 years of age the lymphocytes dropped to 25% sion of peripheral blood elements in the exposed people makesit appearlikely that thereis slight of the levels in the comparison children, but showeda slight rise during the following weeks. residual bone marrow damage. A general anemic tendency has been evidentin The lymphocyte level showed slight increase by 1 year. In the following year mean counts apboth exposed and unexposed Marshallese. PriceJones curves, on the average, showed slight proachedthelevels of the comparison population microcytic tendency. Serum iron levels have been but remainedslightly below (see Figures 50 and 65). generally normal, and the cause of this anemic Neutrophil levels fluctuated considerably during tendency has been undetermined. the first month; possibly this was related to the Reticulocyte counts have been about the samein prevalence of beta burnsof the skin during that the exposed as in the unexposed people. period. Neutrophil depression became evident by Clinical findings, except for radiation-induced 5 and 6 weeks post exposure (see Figures 49 and lesions of the skin, patchy epilation, and early 65), with levels reaching about half that of the gastrointestinal symptoms, revealed no clear-cut comparison population in the adults andslightly disease processes or symptoms which could bere- smaller.gréup-en Ailingnade.aaRongerik showed