¥ GROWTH AND RADIATION delivered to the thyroid did not result in any clinically apparent metabolic dysfunc- in March, 1954, have shown retardation in exposed Rongcelap children. Persistent en- both statural growth and skeletal maturation among the exposed boys as compared to non-exposed comparison children. The retardation was noted among boys who were under 5 years of age when exposed under identical condition. Thus, it is be- of exposure. Nostatistically significant dif- tions and repeated determinations of the serum protein-bound iodine values have been about the same in exposed and un- vironmental factors are eliminated since both exposed and control populations live lieved that in these Marshall Islands children any radiation effect on bone growth must have resulted from penetrating gamma radiation at the time of original exposure. As pointed out above, the ac- cumulated dose to the bones from absorbed radionuclides, such as Sr, is believed to be negligible compared with the dose of gamma radiation originally received. How- to the fallout, being most prominent among those who were 12 to 18 monthsold at time ferences were noted in the growth patterns between the exposed and the non-exposed group of girls and between 39 children born to exposed parents subsequenttofallout and 53 children born to non-exposed parents. REFERENCES ever, the dose of penetrating radiation re- 1. Cronkite, E. P., Bond, V. P., and Dunham,C. L.: Some Effects of Ionizing Radiation on Human Beings. A report on the Marshallese osseous growth. In rabbits, D’Angio and radiation injury in the human being. U.S. ceived was much lower than that expected to produce retardation by direct effect on co-workers?’ found that a dose of 400 r to the entire extremity was required before any grossly observable inhibition of bone growth occurred. The possibility that radiation exposure may produce someindirect, abscopal effect on bone growth has been examined by Conard,*® who demonstrated in weanling rats a retardation effect on bone growth of shielded legs when the animals were exposed to 300 to 600 rads. This effect was largely accounted for by radiation-induced lowered food intake and weight loss, though preliminary experiments indicated that the abdominal area might be the site of an additional abscopal effect. It was noted that in 25 of 31 exposed Rongelap children, in whom weights were documented, a weight loss of several pounds each occurred during the first 6- to 8-week period following exposure.:? This may have been reflection of radiation effect on metabolism, but effects of change of environment cannot be ruled out. SUMMARY Longitudinal studies on 38 children who were exposedto fallout radiation on Ronge- lap and Ailingnae atolls, Marshall Islands, IOE2Z5 74 and Americans accidentally exposed to ra- diation from fallout and a discussion of - Atomic Energy Commission TID 5358, Washington, D.C.: U.S. GovernmentPrinting Office, 1956, 106 pp. 2. Cronkite, E. P., Dunham, C. L., Griffin, D., McPherson, S. P., and Woodward, K.T.: Twelve-month post-exposure survey on Marshallese exposed to fallout radiation. Brookhaven National Laboratory (BNL) Technical Bulletin 384 (T-71), 1955. 3. Conard, R. A., Huggins, C. E., Cannon, B., Lowrey, A., and Richards, J. B.: Medical survey of Marshallese two years after exposure to fallout radiation. J.A.M.A., 164: 1192, 1957. 4, Conard, R. A., Meyer, L. M., Rall, J. E., Low. rey, A., Bach, S. A., Cannon, B., Carter, E. L., Eicher, M., and Hechter, H.: March 1957 medical survey of Rongelap and Utirik people three years after exposure to radioactive fallout. BNL 501 (T-119), 1958, 26 pp. 5. Conard, R. A., Robertson,J. S., Meyer, L. M., Sutow, W. W., Wolins, W., Lowrey, A., Urschel, H. C., Jr., Barton, J. M., Goldman, M., Hechter, H., Eicher, M., Carver, R. K., and Potter, D. W.: Medical survey of Rongelap people, March 1958, four years after exposure to fallout. BNL 534 (T-135), 1959, 36 pp. 6. Conard, R. A., Meyer, L. M., Robertson,J. S., Sutow, W. W., Wolins, W., and Hechter, H.: Effects of fallout radiation on a human population. Radiat. Res., Supplement 1, p. 280, 1959. 7. Conard, R. A., Macdonald, H. E., Lowrey, A., oe. 730