RADIATION STANDARDS, INCLUDING FALLOUT 327 Information was obtained from eight British hospitals about 39,166 liveborn children whose mothers were known to have been subjected to abdominal or pelvic irradiation during their pregnancy in the years 1945-56. The children who died of leukemia in this group were discovered by comparing their names with the list of names of all children dying of leukemia in Britain between 1945 and 1958. In the irradiated group, nine were discovered to have died of leukemia before the end of 1958. The expected number, derived from age specific mortality tables, was estimated to be 10.5. In this study there would not appear to be a disproportionate occurrence of leu- kemia among children irradiated before birth. The published data on the leukemogenic effect of irradiation in utero would therefore seem to be conflicting and the earlier reported increased incidence of leukemia in children thus irradiated not established. However, it must be stated that the data of Court Brown and others do notdisprove Stewart’s thesis. What human data are available which might shed light on the relationship of chronic irradiation of the skeleton by bone-seeking radioelements to the induction of tumors? The committee, I hope, will pardon me if I quote from work carried out at the Argonne Cancer Research Hospital and the Argonne National Laboratory by Drs. Asher Finkel, Charles Miller, and myself. These studies represent the first fruits of a renewedeffort to study as many radium-containing individuals as possible, chosen because of occupational or medical history alone and not primarily because of the presence of symptoms. During the past 4 years, 264 persons formerly employed in the radium watch dial industry, or as radium chemists, or who received radium as a form of medica] therapy, have been sought out, found, and measured for radium content. Of these, 233 represent cases previously unreported in the literature, the remainder are earlier cases recently restudied. Approximately 400 women who worked as radium dial painters at some time in the past live in the environs of Chicago. This study, however, has concerned itself almost exclusively with those women whose occupational history antedated 1925. Among the reasons involved in the decision to study the pre-1925 groupfirst were the observation by us that radium burdens were higher in the early group, the longer period during which their skeletons have been irradiated (greater than 36 years), and the older age of the group, which made necessary their early study before attrition from the diseases of aging reduced the numberavailable for study. Of the 264 persons whose body radium content has been accurately determined, it has been possible to complete detailed radiographic studies of the entire skeleton of 236. Parenthetically, may I add that two other research groups in the United States are at present carrying on similar studies of former radium dial painters; one at the Massachusetts Institute of Technology, and the other at the New Jersey State Department of Health. The objectives of our group include the correlation of body content of radium to certain destructive changes in the bone, to tumors of bone and other structures surrounded by bone, and to the incidence of leukemia. Gyetiageereeitieaeeeoshiah ble oad RRRT Re ERAMEDS