The majority of data reported have been obtained at LASL or at the Argonne National Laboratory (ANL). In the first case, a large liquid scintillation counter is used, and at ANLa large sodium-iodide crystal is the detector. The liquid scintillation system is more rapid, but the sodium-iodide crystal apparently has a better energy resolution. The data from LASL are reported in Tables 48a through 48d. Control subjects were run at both laboratories to show time trends, whereas the general samples run at LASL were mostly visitors to the Laboratory. Data from ANL are reported in Table 49. a. LASL Whole-body Measurements. The LASL measurements were carried out ona number of control subjects during 1956 (Table 48a) and 1957 (Table 48c). Control subjects show the time trend of the human Cs'* burden at the particular location of the laboratory. The indicated ratios in all cases are less than 1, indicating that the gamma dose from cesium is only a fraction of that delivered by potassium. It has been customaryat the laboratory that all visitors to the Biomedical Research Group are measured in the whole-body counter. This has given a large number of results on individuals from other states and other countries. The data have been summarized in journal articles,» and the conclusions drawn in these articles will not be repeated here. On the other hand, the articles could only summarize the entire mass of data, and it was felt that this detailed material should be available. b. ANL Whole-body Measurements, The large crystal spectrometer at ANL has been used for whole-body measurements on a series of control subjects since 1955. These data are shown in the figure shown with Table 49. They have concluded that the average Cs‘*" body burdens have remained essentially constant since the spring of 1956, with the exception of minor fluctuations due to dietary changes. m wh ee REFERENCES . J. L. Kulp, et al., Strontium-90 in Man, Science 125: 219 (1957). . WwW, R. Eckelmann,et al., Strontium-90 in Man—lIl, Science 127: 266 (1958). E, C. Anderson, et al., Radioactivity of People and Foods, Science, 125: 1273-1278 (1957). . &E, C. Anderson, World-wide Distribution of Cs-137, (to be published). 63