5 mortality from whole-body radiation injury.? Therefore, in view of the low leukocyte counts that developed in the Rongelap people, the use of prophylactic administration of antibiotics was given careful consideration. Twentyseven individuals had absolute neutrophil counts of 2,500 per cubic millimeter or less at some time during the period of observation. Temporary depressions as low as 700-1,000 were observed. Prophylactic admininistration of antibiotics was not instituted because all individuals were under continuous medical observation and it was felt that such drugs might obscure medicalindication of treatment and lead to the development of drug-resistant organisms. An epidemic of upper respiratory infection developed between the 27th and 47th days after exposurein al} of the exposed groups. Fifty-eight per cent of the Rongelap people were involved. The disease did not appear to be more severe in this than in the other less exposed groups. There was no correlation between leukopenia and incidence of infection. Platelets were first counted 10 days after exposure (fig. 2), at which time the level in the females were ap- proximately 60% of the appropriate control group. After this, the platelet count fell, reaching a low of approximately 30% of the control value during the fourth week. (At this time counts in 20% of the Ronge- lap people were below 90,000 platelets per cubic millimeter.) The platelet level rose during the fifth and sixth week and had reached the value noted for the initial counts on the 10th day. A second decrease in platelets developed during the seventh and eighth week, and values remained at approximately 70% of the control values during the remainder of the observation period. The pattern of the platelet counts in the male groups was similar to that noted for the females. Counts of the lower 2. Dunham, C. L.: Cronkite, E. P.; LeRoy, G. V., and Warren, S.: Atomic Bomb Injury: Radiation, Council on National Emergency Medical Service, J, A. M. A. 147: 50 (Sept. 1) 1951. Cronkite, E. P., and Brecher, G.: Defects in Hemostasis Produced by Whole Body Radiation, in Clotting and Allied Problems: Transactions of the Fifth Conference, January 21 and 22, 1952, edited by Joseph E. Flynn, New York, Josiah Macy, Jr., Foundation, 1952. Bond, V. P.; Silverman, M. S., and Cronkite, E. P.: Pathogenesis and Pathology of Radiation Infection, Radiation Res. 1: 389, 1954. Cronkite, E, P., and Brecher, G.: The Protective Effect of Granulocytes in Radiation Injury, Ann. New York Acad. Sc. 59: 815, 1955. 90120493