12 Impairment of hearing was averaged for the two ears as follows: the decibel loss for each of seven frequencies (200, 500, 1000, 2000, 3000, 4000, and 7000) in each ear was averaged to give a mean frequencyloss in decibels for the two ears. Cardiovascular Changes. 1. Systolic and dias- tolic blood pressures were obtained with the standard aeronoid cuff-type sphygmomanometer. Two readings were obtained, and the average value was used. There wasno basic or adjusted level of physical activity such as resting for a standard period prior to the readings. Pressures were taken on the Jeft arm with the subject supine during the course of the physical examination. 2. The degreesof peripheral arteriosclerosis and retinal arteriosclerosis were scored on a O to 4+ scale. The former was estimated by palpation of the peripheral]arteries, the latter by viewing the retina with an ophthalmoscope. Neuromuscular Funcfion. Neuromuscular function was measured by having the subject depress the key of a handtally type of blood cell counter as many times as possible in the period of one minute. The total numberof depressions represented the score. Hand Strength. Hand strength was measured by a Smedley hand dynamometer.* Thespring tension of the hand grip was measuredin kilo- grams. The maximum squeeze strength in the dominanthandin threetries was recorded. Handling of Data. Because of sex differences, ee Ai eh oF ee’ ee a : Nee aie ae some of the abovecriteria were evaluated sepa- ratelyfor the two sexes; these were baldness, neuromuscular function, and handstrength. In order that the estimated and measured data could be compared and combined, both types of data were converted to a percentagescale. The estimated values 0,1+,2+,3+,and 4+ werepresented also as 0, 25, 50, 75, and 100%, respectively. In the case of the measured data, the values associ- ated with least aging were taken as zero percent (sometimes the highest reading, as with hand strength; sometimes the lowest, as with hearing loss), and those indicating most aging as 100%. The data were examined on both an individual basis and a population basis. A mean age score was obtained for each individual by averagingall his percent test values. In studying population trends, means were calculated for each criterion by 5-year age groups (in most cases) including *C.H.Stoelting Company, Chicago, I. combined exposed and unexposed populations; these were plotted, and a curve was drawn accord- ing to the best fit by eye. A curve was obtained in the same wayof the 5-year group means of the individual mean age scores. The combining of scores into 5-year age groups was done to reduce possible errors due to the uncertainty of the exact age of some individuals. DOE ARCHIVES Laboratory Procedures Hematological Examinations. Two complete routine blood counts were done, about a week apart, and a third was done on persons showing abnormalities. White blood counts, red blood counts, and Price-Jones curves (for determination of red cell size distribution) were obtained with the electronic Coulter, which proved verysatisfactory and time-savingfor this type offield examination. Differential counts were performed in the usual mannerafter staining with Wright’s fluid. Platelet counts were done by phase microscopy, and hemoglobin was determined by the cyanhemoglobin technique with the Lumitron colorimeter. Serum proteins were determined with the Hitachi refractometer. Blood and serumsamples for the studies described belowwere collected in the field, kept under refrigeration, and shipped by air to the various laboratories in the United States for analysis. Urine Analyses. Routine urine analyses were carried out on all people receiving physical examinations. These included determinations of protein and hyperglucosuria by reagent paper strips.* In al] cases showing positive findings, the urine was centrifuged and the sediment examined mic- roscopically. In the four cases showing positive urine sugartests, fasting blood specimens were ob- tained and analyzed for blood sugarat the Naval Dispensary on Kwajalein. Serum Cholesterol. Serum cholesterol was determined in blood samples drawn from exposed and unexposed Rongelap people, and also in about 70 blood samples from people at Utirik Island and 63 from people at Majuro Atoll. These analyses were done at the National Institutes of Health by Dr. J.-H. Bragdon and Mr. J.C. Lauter. Complement Fixation Tests. Serum samples ob- tained from 163 exposed and unexposed Rongelap people were frozen and sent to the National Institutes of Health for various examinations. Com*Clinistix, Ames Company, Inc., Elkhart, Indiana.