Figure 9. Typical Marshallese living conditions at Utirik. tal examinations were carried outon all persons >40 years of age. This included in the case of men palpation of the prostate gland. Radiographs of the chest and other parts of the body were obtained as indicated. Hematological data were obtained and were available for evaluation. In detection of possible leukemia (or preclinical evidenceof incipient leukemia) the lymph nodes and spleen were carefully examined; hematological data were analyzed,including routine hemograms and percent basophils in 4000 white cell count; and alkaline phosphatase smears of the white blood cells where done were available for review. LABORATORY PROCEDURES Hematological studies included white cel! counts with differentials, red blood counts, hematocrits, hemoglobins, platelet counts, serum proteins, blood smearsfor alkaline phosphatase, and basophil countstudies. Techniquesfor these procedures have been described in previous reports.'’? Bone marrow aspirationsfor differential study were collected on 4 exposed and 2 unexposedindividuals. Considerable effort was spent on chromosome studies in the past two surveys. Of particularinterest was the possibility of studying the chromosomesof cells cultured from the “beta burn” areas of the skin. Some 50 skin biopsies were obtained and successfully grown in most cases. However, contamination of these cultures occurred under the field conditions of these studies, and unfortu- co cm cf nately all were lost before they could be broughtto b 199 the stage of chromosome preparations. Chromosome studies of peripheral blood cultures, however, have been considerably more successful. During 1963 a large numberof bloods were cultured suc- cessfully. However, the final chromosomespreads in many cases were not completely satisfactory, and the study was repeated during the 1964 survey. At this time successful 2- and 3-day blood cultures were obtained on 64 exposed people and 11 unexposed. Excellent growth and chromosome spreads were obtained, and the slides are now being evaluated.* Sera were collected both years on most individuals, and the following examinations were carried out in U.S. laboratories: protein-bound iodines on 9 exposed and 8 unexposed people and a few blood sugar determinations;** serum folic acid levels on 52 exposed and 85 unexposed people.*** During the 1963 survey 38 urine samples were collected, and during the 1964 survey 27 samples, for radiochemical analyses.* Most of these were 24-hour samples, though several pooled samples were obtained. Most were from people living on Rongelap Island, but some were obtained at Ebeye. * Assisting in these studies are Dr. Shields Warren and Dr, HermannLisco at the New England Deaconess Hospital, Miss Agnes Stroud at Argonne National Laboratory, and Miss Patricia Crumrine at the Women’s Medical College, Philadelphia. We are grateful to Drs. Michael Bender and Carolyn Gooch of Oak Ridge, W.M. Court-Brown of Edinburgh, Scotland, and Kurt Hirshorn of New York University for advice. **Dr L.V. Hankes and the Clinical Chemistry Group in the Medical Department of Brookhaven National Laboratory were responsible for these analyses. ***Dr. Thomas Lynch, Hackensack Hospital, Hackensack, N.J., did the folic acid determinations. +Dr. Edward Hardy andothers at the AEC Health and Safety Laboratory, New York, N.Y., carried out these analyses.