it | World Wide Values Ss a — The Cs/K ratios present in the 13 Argonne control subjects (Chicago) are givenin Table 7. These values range from 22 to 50 Uc Cs'37 per gram of body potassium with an average value of 36 ypc Csl37/g K, irrespective of sex. 2.3. The spread from the lowest to the highest value yields a ratio of 1 to This ratio was also determined for 1] Central and South American subjects during their visit to our Laboratory. The values vary from 7 to that the subjects with the larger Cs!*? body burdens were the larger consumers of meat and dairy products as is invariably the case with North American control subjects. The diets of the Argentine subjects, however, include meat and dairy products in quantities wholly comparable to the U.S.A. diets and, moreover, their Cs!*? body burdens are the lowest of the | group. This fact points to the possibility of a real difference in hemispher- ical fallout. . The values found for people from otherareas of the worldare given by Table 9. The average for the European subjects is 32 jipc Cs137/¢ K, essentially identical to the Chicago value. The Asian subjects who include little or no milk in their diets are significantly lower .(1) The similarity between the European and Chicago and continental U.S.A. values (2) suggests that the fallout in the Northern Hemisphere is approximately uniform. : _ Although the evidence gathered on a few subjects is certainly not conclusive, it does, nevertheless, focus attention on the various factors affecting the geographical patterns of fallout which have been considered for the case of 52% The Cs'3? Atmospheric Content as a Function of Time In conjunction with our studies of the time trend of Cs}37 content of humans at Chicago it was thought advisable to inquire into the Cs'37 content of the atmosphere at the same site. The gross amount of radioactivity present in the air has been measured at Argonne National Laboratory for the past several years. Air pumps located at several different sites at Argonne pull approximately 15 m? of air per hour through HV-70 counting filter papers. The filters from some air pumps were changed daily and some were changed weekly. The weekly filter papers were bunchedinto monthly ' groups and the gamma-ray spectra of each bundle obtained. Be 5.0 | Pio ween ee dietary influence is pretty well established, the conclusion could be drawn for pe Since the spread of each group is approximately the same and the a 21 ppc Csi97/g K with an average value of 14.6 ppc Cs37/g K and yielda spread of 1 to 3. ey eesPn,te yet BRR OR el REE Prag a Bee cogerE TGtet dole eg Se PE asae neEE we ~ sate Table 8 according to geographical latitude. These data are tabulated in