An attempt is also being made to study aging from a more quantitative clinical approach. Certain criteria usually associated with aging that can be easily obtained on physical examination are recorded as nearly quantitatively as possible either by direct measurement or estimation of degree of severity of criteria in a scale from 0 through 4 --. This work is in the early stages and will not be reported at this time. The approach is believed worth investigating since many animal studies indicate late radiation changes that closely resemble advanced or premature aging [Blair (1952), Cassarett (1956), Alexander (1957)]. Malignancies, lenkemia. One case of ovarian cancer (verified by biopsy at operation) in a 61 year old exposed female was noted during the past year, the first case of malignancy noted in either the exposed or unexposed group. — There is no reason to incriminate radiation in the etiology of this case, particularly in view of the early time of appearance. Since leukemia is the carliest type of neoplasia associated with radiation to develop, examination of the Marshallese has included blood smears stained for alkaline phosphatase of neutrophils and the numbers of basophils per 4000 white cells per individual, but no evidence of decreased alkaline phosphatase in the neutrophils nor increased basophil counts indicative of incipient leukemia was noted. An increased incidence of leukemia has been reported in radiologists [ March (1947), Ulrich (1946), Warren (1956)], in children receiving therapeutic radiation in infancy for thymic enlargement [Simpson and Hemplemann (1957)], in children exposed in utero from diagnostic x-ray examinations of the mothers | Stuart, et al (1956)], and in patients receiving x-irradiation for treatment of ankylosing spondilitis [Court-Brown and Doll (1957)]. In survivors of the atomic bombs in Japan [Maloney and Kostenbaum(1955), the incidence of leukemia was significantly increased, but nevertheless the total incidence was low. Therefore, since the exposed Marshallese population is small, it does not seem likely that leukemia will be observed as a result of their radiation exposure. Cataracts, During the past five vears repeated slit lamp ophthalmological observations in the Marshallese revealed no opacities typical of the radiationinduced type. The induction of opacities of the lens by radiation is a well established fact in man. In the Japanese exposed to the atomic bombs opacities of the lens, including about 10 severe cataracts, have been observed [ Cogan, et al (1949, Sinsky (1955)]. Merriam and Fecht (1957) on the basis of clinical cases of radiation-induced opacities calculated that 200 r was the minimum dose of gamma or x-irradiation resulting in lens opacities. Therefore, the dose of radiation received by the Marshallese may be too low to result in such changes. 320 5042293