36 However, since the latter children were on the average 4 months older, the data did ne*justify a conclusion that the difference in stature was associated with the exposure of the parents.: Residual beta burns of the skin consisting of studies were carried out on samples from a number of people. Successful cultures were obtained in rations, and hyperkeratosis were noted as in past surveys in about 10 people. During the past several years an increase in the number of pigmented nevus-like lesions has been noted in areas previously involved with beta burns, These appear to of dicentrics along with abnormal diploid numbers varied degrees of atrophy, scarring, pigment aber- be increasing slightly in number. Histological diag- nosis of one such lesion that was biopsied indi- some 40 of 70 bloods; however, difficulties were encountered under field conditions of high temperature and humidity in obtaining satisfactory chromosome smears. Nevertheless small numbers were noted in a few smears. These data suggest that resistant damage to blood cells occurred, and during the next survey further chromosomestudies of blood and skin of beta burned areas and possibly of bone marrows are being planned. Gamma spectrographic analyses were not car- first-generation Japanese children of exposed par- ried out this year since previous levels of gamma emitting isotopes (Cs? and Zn*) had not shown significant further increase at the time of the 1961 survey. However, urinary excretion of Srwas determined by radiochemical analysis on 24-hr samples from 18 exposed and 9 unexposed people. As previously noted, there were no differences be- little in the way of congenital anomalies in the children of exposed parents. One baby born of an exposed mother in 1960 was diagnosed as having levels of Sr**. The mean level of Sr was 114 +14 pC/g Ca. Onthe basis of previous calculations, the estimated body burden of Sr® was 12.0 mC, cated that it was a typical pigmented nevus. No case of chronic radiation dermatitis or malignant changein the residual burns was noted. Genetic studies have not been specifically conducted in view of the small population involved and the generally negative results of the studies on ents. However, routine examination has revealed congenital heart disease and died several months after birth. The suggested evidence of increased miscarriages andstillbirths in the exposed woman during the first several years after exposure might be related to irradiation of the germ plasm, although this tendency was not apparent in recent years. Hematological studics showed mean leukocyte levels lower this year than last year in both exposed and unexposed groups, but the exposed group continucd to show lower neutrophil and lymphocyte levels than the unexposed group. Platelet levels were higher this year in both groups than previously, but the exposed group continucd to show slightly lower levels. There was an increase in erythrocytes in both exposed and unexposed groups, with little difference noted between the groups. The deficit in leukocytes and platelets in the exposed people was more apparent in the younger and older groups than in the middle group. Bone marrow examinations showed a reduced myeloid-erythroid ratio in 8 of 9 cases with abnormalitics of the erythroid and myeloid pre- cursors in some. In view of these findings, it is believed that there is some residual effect of radiation exposure on hematopoicsis in these people. Peripheral blood cultures or chromosome tween the exposed and the unexposed urinary which is about 6% of the MPC (200 m,zCfor non- industrial populations). Several bone samples obtaincd from autopsy on the 78-yr-old exposed woman showed an average of 15 pC/g Ca, representing a body burden of 11.4 muC or about 5.7% of the MPC, which compares favorably with the estimate based on urinary excretion. These levels represent about a sixfold increase in Sr™ over the 1958 levels. Analysis of 4 coconut crabs from the Island showed high levels with little reduction during the past few ycars, necessitating a continuation of the ban on eating these crabs. Although the acute effects of radiation exposure in the Marshallese have largely subsided, it is possible that certain late or delayed effects may occur. Some late effects have already been observed in the Japanese, such as an increased incidence of leukemia and possibly other malignancies and also development of cataracts. Still other late effects have been observed in irradiated animals. It is unlikely that such abnormalities will develop in the relatively small Rongelap population, and, should they develop, the incidence should be quite, low. Nevertheless, it is extremely important that further surveys be conducted to detect subtle changes associated with the development of such abnormatities so that they can be documented andtherapeutic