showed greatest deficits in the older exposed age groups. The results of the immunodiffusion studies are shown in Table 2 and in Fig. 4. Parallel to the increase in serum gamma globulin levels, the immunoglobulins showed increasing values in the older age groups of the unexposed people. The increase in IgG moiety was most pronounced and showed significant correlation with age (r=0.78). ‘The increase in the other immunoglobulins did not show a high correlation with age. The increase in the K light chains was highly ¢orrelated with age (r=0.96). _ Higher K/L ratios were noted in the older people though there was no Significant correlation with age (r=0.46). In the exposed population all of the immunoglobulins were depressed below levels of the unexposed group, the most pronounced depression was in the IgG and IgA moieties and in the L light chains. . DISCUSSION | . : ' Though the role of immune mechanisms in the aging process has never — been clearly defined, it is generally agreed that such mechanisms are impaired in senescence. Ram(1967) in an excellent review of the subject pointed out that "i .....it is well established that the capacity for immune . responses increases during neonatal and juvenile life to a maximum in the young and adult animal, it remains constant for a time and then gradually decreases as the animal ages." The results of the present studies in the Marshallese people seem generally to support this thesis. - Before discussingthe results of these studies, a few pertinent remarks should be made concerning the Marshallese people under study. This population is in many Ways not comparable with a population in the United States in view of certain environmental and racial differences. t ‘' t‘ 4 ' As is generally true