32 The various changes generally associated with physiological senescence are known to showwide 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 ofaging than others, judging by the degree of change and the variability of the data observed. (This statement is not based onstatistical analysis.) Someof the better criteria appeared to be accom- a Te modation of the 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 1? F 24 F 26 39 Age Description 9 Shght depigmentedscars,left antecubital fossae. 19 Mottled spots of pigmentation and depigmentation, dorsum offeet. M18 Marked scarring between first and second toes, right foot, with binding to subcutaneoustissues. Areas of lesser involvement peripheral] to this area. No evidence of chronic radiation dermatitis. F 20 Slight mottled pigmentation-depigmentation with little scarring, dorsum of feet. Mottled hyperpigment- 49 F 21 59 F 40 63 F 42 67 F 20 78 F 43 79 M 45 ed spots persist on back of neck. Black moles believed to have in- creased in number overright side of neck, also several noted in left antecubital fossa. Mottled roughening and pigment variation, back of neck. Mottled pigmentation, left side of neck, with shght roughening ofskin. Depigmented scarred areas with slight atrophyof skin over dorsum of feet, particularlyat site of deeper scar on left foot. Some areas adjacent to scars showincreased pigmentation. Pigmented moles appear to haveincreased in number over left side of neck and to lesser extent on right side at sites of rather deep beta burns. Backof left ear shows depigmented scar with some binding down to cartilage. No evidence of breakdown. scoring of the latter. This appeared generallyto be the case, but the estimated values for greying of the hair and arcus senilis correlated surprisingly well with age. The amount of subcutancous fat probablyinfluenced measurementsofskin looseness, but, since loss of subcutaneousfat is some- what age dependent, probably in the right direction. It is hoped that in the futurestatistical treatment of the data mayfurnish a weighting factorfor each criterion based on the degree of age-associated change andthe variability of the data. Itis not always possible to run the complete battery of tests on each individual, and use of such weighting factors would tend to minimize the disparity due to the omissions. The data presented must be consideredas preliminary in nature andto represent only a small fraction of the many varied changesassociated with the aging process. Under the conditions of examinations of the Marshallese, the battery of tests employedis necessarily limited. As more experience is gained, someofthe tests may be eliminated and new ones 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 means of assaying “biological age” which might be of use in studying the possible effects of radiation on the aging phenomenon in human beings. In the case of the exposed Marshallese, results of further aging surveys will be carefully evaluated, and the results DOE ARCHIVES Figure 32. Residual scarring between first and second toes, right foot, from beta burns, 5 years post exposure (Subject +26).