tion must be exercised in evaluatingthe results of these studies on genetically inherited characteristics because of the small number of samples tested. The data do seem to indicate relative homogeneity of the population andclosest kinship with people of Southeast Asia. These data also maybe useful as a base line should genetic changes appear in later generations, possibly related to radiation exposure. Results of other laboratory studies included the following: Serum protein levels were generally on the high side of normal; electrophoretic patterns showed the increase tn proteins was largely due to an increase in the gammaglobulin fraction. The reason for this is not apparent. Numerouschronic infections may be an explanation. Sodium levels in the urine and food indicated about the same consumption of NaCl as in Amer- icans. The generally lower incidence of hypertension in the Marshallese might be related to the fact that the former native diet was probablv lower in salt content than the present, more westernized diet. It will be interesting to see whethertheincidence of hypertension will later increase. Serum cholesterol levels (1957, 1959) were some- what lower in the exposed population than in the comparison or, Utirik populations, but were in the low normal range. No abnorally low readings were noted. Serum creatinine levels (1957) were in the normal range with no abnormallevels noted. Serum vitamin B,, concentrations (1958, 1959) were generally significantly higher than American levels. The possibility of contamination of the samples with bacteria producing vitamin B,, must be considered, since myeloproliferative and liver diseases were not seen. Serum protein bound iodine levels (1957, 1959) were generally slightly elevated. Evidence for thyroid dysfunction was not apparentin the people. Glucosuria and elevated blood sugar were found in 4 unexposedindividuals, which indicated a rather high incidenceof diabetes. A survey for intestinal parasites (1958) showed 75% of the people to be infected with various types. For the three major pathogensfound, the overall infection rates were, for Entamoeba histolytica, 18.2%; for hookworm, 5.5%; and for Trichumis trichwura, 34.3%, Eostnephiltia >5% has consistently been noted in about half the people. The fact that half the cases with eosinophilia showed no helminthicinfections at all suggests that other factors besides parasitic infections must be responsible. The eosinophilia may be related to chronic fungus and other infections, particularly of the skin. Complementfixation studies for parainfluenza1, 2, and 3, respiratory syncitial, psittacosis, and Q fever showed antibodiesto all groups of viruses except that for Asian influenza, which probably had not vet seriously involved the people of the Marshall Islands. The antibodvtiters appeared to be somewhatlower in the exposed people. DIFFICULTIES ASSOCIATED WITH THE EXAMINATIONS As mentioned in previous reports, several diffi- culties were associated with carrying out the examinations as well as interpreting the findings. 1. The language barrier made examinations difficult, since very little English is spoken by the Marshallese. However, there were sufficient English-speaking Marshallese to assist the medical team in most instances. 2. The lack ofvital statistics or demographic data on the Marshallese imposed a seriousdifhculty in interpretation and evaluation of the medical data. Recordsof births, deaths, etc., have been made bythe health aides or magistrates of the vil- lages and supposedly forwardedto thedistrict ad- ministrator; however, such records have been incomplete or lost in most instances, and vitalstatis- tics are therefore inadequate. Trust Territory officials are now attempting to assemble such data. 3. There is uncertainty on the part of some of the Marshallese as to their exact ages, particularly among the older group. This imposes certain difficulties in interpreting some of the studies to be outlined. COMPARISON POPULATIONS During thefirst 2 years, two separate groups of Marshallese people were used for comparison, each of comparablesize to the exposed Rongelap group and matched for age and sex. However,this population was found to be unstable, with a large attrition rate over the 2 years, which madeit unsatisfactory. At the time of the 3-year survey, it wasfound that during the preceding 12 months the Rongelap population at Majuro Atoll had