4 levels in the Marshallese appeared to be above the average in the U.S, population. Dental surveys" showed nosignificant differences in caries rate between exposed and unexposed groups. However, the incidence and severity of with the possible exception of suggestive evidence of increased miscarriages and stillbirths in the ex- posed women andthe slight retardation of growth noted in the male children of exposed parents. peridontal disease was slightly greater in the ex- BETA IRRADIATION OF THE SKIN finding is related to radiation effects. The poororal hygiene generally observed in the Marshallese had the radiation dose to the skin. Beta burns of the posed group. It is not known whether or notthis its usual results, namely, high caries rate in teen- age children, severe pceridontal lesions in adults (heavy calculus and loss of alveolar bone), and edentulous mouths in the aged. Radiation exposure It was impossible to get an accurate estimate of skin and epilation appeared about 2 wecks after exposure, largely on parts of the body not covered by clothing. About 90% of the people had these burns, and a smaller number developed spotty did not appear to have affected developing denti- epilation of the scalp. Most of the lesions were Late effects of radiation. Various parameters usually associated with aging were measured or estimated on a 0 to 4+ scale (skin looseness, elas- scaly desquamation, and were associated with little tion in the exposed children. ticity, and senile changes; greying of the hair and balding; accommodation, visual acuity, and arcus scnilis; hearing; cardiovascular changes including blood pressure and degrees of peripheral and retinal arteriosclerosis; ncuromuscular function; and hand strength). Comparison of these measure- ments in exposed and unexposedindividuals of the same age groups showed no apparent differences. A biological age score wascalculated for individuals and groups by use of an average percentage score. Life shortening effects of radiation have not been apparent. As noted, the mortality rate was about the same in the exposed as in the unexposed people. The one case of cancer that developed in the exposed group occurred at 5 years after exposurc, too soon, it is believed, to bear any particular relation to radiation exposure. Leukemia surveys including physical findings, studies of white cell counts and types, alkaline phosphatase staining, and basophil counts of 4000 white cells showed no evidence of leukemia or Icukemic tendency. One child in the irradiated group has hadslightly elevated basophils but no other positive findings. The cardiovascular and arthritis surveys, as well as the general results of the physical examinations, have not shown any apparent increased incidence of degenerative diseases in the exposed people. No radiation-induced cataracts have been observed in any of the exposed people. Genetic effects have not been specifically studied because of the small number of people involved. No apparent radiation-induced genetic changes have been detected on routine physical examination in the first-generation children of exposed parents, superficial; they exhibited pigmentation and dry, pain. Rapid healing and repigmentation followed. Some lesions were decper, showed wet desquamalion, and were more painful. A few burns became secondarily infected and had to be treated with antibiotics. Repigmentation of the lesions gradually took place in most instances, and the skin appeared normal within a few weeks. However, in about 15% of the people, deeper lesions, particularly noted on the dorsum ofthe fect, continued to show lack of repigmentation with varying degrees of scarring and atrophy of the skin. By 6 years the only residual effects of beta radiation of the skin were seen in 10 cases which showed varying degrees of pigment aberrations, scarring, and atrophy at the site of the former burns. During the past several years an increased number of pigmented maculae and moles have been noted in previously irradiated areas ofthe skin, but these have appeared to be quite benign. Numerous histopathological studies have been made,'** and the changes found have been consistent with radiation damage. At no time have changes been observed either grossly or micro- scopically indicative of malignant or premalignant change. Spotty epilation on the heads was short lived, regrowth of hair occurring about 3 months after exposure and complete regrowth of normal hair by six months. No further evidence of epilation has been seen. An interesting observation noted during the first few months after exposure was the development of bluish-brown pigmentation of the semilunuar areas of the fingernails and toenails in about 90% of the people. By 6 months this pigmentation had disappeared, having grown out with the nail. The cause of this phenomenon has not been explained.