32 The various changes generally associated with physiological senescence are knownto show wide variability among individuals of the same age, and this was borne out by these data. However, some of the criteria appeared to be better indices of aging than others, judging by the degree of change and the variability of the data observed. (This statement is not based on statistical analysis.) Someofthe better criteria appeared to be accommodationofthe eyes, visual acuity, skin retraction, arcus senilis, greying of the hair, and hand strength. The measured criteria would be expected to be morereliable than the estimated ones in view of the subjective element and less precise Table 20 Residual Beta Burns, 1960 Subject No. Sex 17 F 24 F 26 M 39 49 F F scoring of the latter. This appeared generally to be the case, but the estimated values for greying of the hair and arcussenilis correlated surprisingly well with age. The amountof subcutaneousfat probably influenced measurementsofskin loose- ness, but, since loss of subcutaneousfat is some- what age dependent, probablyin the right direction. It is hoped that in the futurestatistical treatmentof the data mayfurnish a weighting factor for each criterion based on the degree of age-associated change andthe variability of the data.It is not always possible to run the complete battery of tests on each individual, and use of such weighting factors would tend to minimizethe disparity due to the omissions. The data presented must be considered as pre- liminary in nature and to represent only a small fraction of the many varied changes associated with the aging process. Underthe conditions of Age Description 9 Slight depigmentedscars, left antecubital fossae. 19 Mottled spots of pigmentation and depigmentation, dorsum offeet. 18 Marked scarring between first and secondtoes, right foot, with binding to subcutaneoustissues. Areas oflesser involvement peripheral to this area. No evidenceof chronic radiation dermatitis. 20 Slight mottled pigmentation-depigmentation with little scarring, dorsum of feet. Mottled hyperpigmented spots persist on back of neck. 21 Black moles believed to have increased in numberoverright side of examinations of the Marshallese, the battery of tests employed is necessarily limited. As more experience is gained, someof the tests may be eliminated and newones added. Thetests of vigor are thought to be extremely important in assessing aging, and it is hoped that moretests of this nature may be added. At this time the data are presented to introduce an approach to a feasible meansof assaying “biological age” which might be ofuse in studying the possible effects of radiation on the aging phenomenon in humanbeings. In the case of the exposed Marshallese, results of further aging surveys will be carefully evaluated, and theresults neck, also several noted in left ante- 59 F 63 F 67 F cubital fossa. 40 Mottled roughening and pigment variation, back of neck. 42 Mottled pigmentation, left side of neck, with slight rougheningof skin. 20 Depigmented scarred areas with slight atrophyof skin over dorsum of feet, particularly at site of deeper scar on left foot. Some areas adjacent to scars show increased pigmenta- 78 F 79 M tion. 43 Pigmented moles appear to have increased in number over left side of neck and to lesser extent on right side at sites of rather deep beta burns. 45 Back of left ear shows depigmented scar with some binding downto.cartilage. No evidence of breakdown. Figure 32. Residual scarring between first and second toes, right foot, from beta burns, 5 years post exposure (Subject #26).

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