in the exposed group. It is not known whetherthis findingis of any significance in relation to their radiation exposure. Slit-lamp observations showed no opacities of the lens characteristic of radiation exposure. As a whole, visual and accommodation levels in the Marshallese appeared to be above the average in the U.S. population. Dental surveys showed no significant differences in either caries rate or incidenceof peridontal disease between exposed and unexposed groups. The poor oral hygiene generally observed in the Mar- shallese had its usual results, namely, high caries rate in teen-age children, severe peridontallesions in adults (heavy calculus and loss of alveolar bone), and edentulous mouthsin the aged. Radiation exposure did not appear to haveaffected developing dentition in the exposed children. Late effects of radiation. Various parameters usually associated with aging were measured orestimated on a 0 to 44. scale (skin looseness, elasticity, and senile changes; greying of the hair and balding; accommodation, visual acuity, and arcussenilis; hearing; cariovascular changesincluding blood pressure and degrees of peripheral and retinal arteriosclerosis; neuromuscular function; and hand strength). Comparison of these measurements in exposed and unexposed individuals of the same age groups showed no apparentdifferences. A biological age score was calculatedfor 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 exposure, 100 soon, it is believed, to bear any particularrelation 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 leukemic tendency. One child in the irradiated group had 3% basophils but no other positive findings. The cardiovascular and arthritis surveys, as well as the general results of the physical examinations, have not shown anyap- parent increased incidence of degenerative diseases in the exposed people. No radiation-induced cataracts have been observed in anyof the exposed people. Genetic effects have not been specifically studied —_ y =:t wd F-~2 gq CT oc cli 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. If the suggestive evidence of increased miscarriages andstillbirths in the exposed women istrue, this may represent a genetic effect of exposure. BETA IRRADIATION OF THE SKIN It was impossible to get an accurate estimate of the radiation dose to the skin. Beta burnsof the skin and epilation appeared about 2 weeksafter exposure, largely on parts of the bodynot covered by clothing. About 90% of the people had these burns, and a smaller number developed spotty epilation of the scalp. Most of the lesions were superficial; they exhibited pigmentation anddry, scaly desquamation, and wereassociated with little pain. Rapid healing and repigmentation followed. Somelesions were deeper, showed wet desquamation, and were more painful. A few burns becamesecondarily 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 feet, continued to show lack of repigmentation with varying degrees of scarring and atrophyof the skin. By 6 years the onlyresidualeffects of beta radiation of the skin were seen in 10 cases which showed varying degrees of pigment aberrations, scarring, and atrophy at thesite of the former burns. Numerous histopathological studies have been made,'*’ and the changes found have been consistent with radiation damage. At no time have changes been observedeither grossly or microscopically indicative of malignant or premalignant change. Spotty epilation on the heads wasshort lived, regrowth of hair occurring about 3 months after exposure and complete regrowth of normal hair by six months. No further evidenceof epilation has been seen. An interesting observation was the appearance of a bluish-brown pigmentation of the semilunar areas of the fingernails and toenails in about 90% of the people, beginning about 3 weeks after exposure. By 6 months, this pigmentation had largely grown out with the nail and had disappeared in most cases. The cause of this phenomenon has not been explained.