23 ranged from 20 to 26 months, with an average of 22.4 months. To determine whether or not some pattern in physique characterized these children with retarded osseous development, several physical measurements (from the 1959 study) on them and on their sibs were compared (Table 13). These anthropometric data suggested twotrends.First, the weight rankings corresponded to chronological age rankings and notto statural rankings. Second, the lack of synchrony in rankings of several measurements was noticeable in those children who were shorter than their youngersibs. This contrasted with the uniform ranking of all measurements in those whose statural ranking corre- sponded with the chronological age ranking. It might be speculated from these limited observations that these children were exposed to radiation at a particularly vulnerable age and that the resulting retardation in osseous development led to failure in statural growth. On the other hand, it is not possible to exclude completely the pos- sibility that some process unrelated to radiation damage was responsible for the retardation in skeletal development. ADULT ABNORMALITIES Table 14 is a compilation of the various physical abnormalities noted in the adult group during the 1959 and 1960 surveys. No abnormalitiesare included for 1960 in the unexposed group because this group was not examined in the 1960 survey. This table does not show any significant differences between the abnormalities noted in the exposed andin the unexposed populations. Results of special examinations are discussed below. CARDIOVASCULAR SURVEY The cardiovascular findings may be foundin the table of physical abnormalities (Table 14). The incidence of various electrocardiographic abnormalities is shown in Table 15. The population was divided into a younger group, aged 20 through 49, and an older group, aged >50. In the exposed population, the younger group of 24 people showed no major abnormalities, but of the 14 older people 29% showed one or more abnormalities. In the unexposed population, among the younger group 15% had one or more abnor- malities, and in the older group 41%. Specific findings may be summarizedas follows. Electrocardiographic Findings 1, Rhythm. In the younger group of exposed subjects, all had normal rhythm. One abnormality of rhythm was seen in a memberof the younger unexposed group.In the older groups, arrhythmia occurred in 3 of 14 exposed individuals and in 4 of 29 unexposed. 2. Conduction Times. Few abnormalities were seen. No individual in either the exposed or the unexposed group had prolongedauriculoventric- ular conduction time (P-R interval) above normal. Several subjects had the shorter conduction time of 0.12 sec; this is considered normal. Theintraventricular conduction time (QRSinterval) was prolongedin several subjects. In the younger unexposed group, the QRSinterval was 0.10 to 0.11 sec In one subject, sufficient to be considered right bundle branch block. In the exposed population the intraventricular conduction time was pro- longed to 0.12 sec in only one individual, age 81, who had a marked degree of hypertensive and arteriosclerotic cardiovascular disease and cardiac enlargement. Among 29 individuals in the older unexposed group. two showed intraventricular conduction times uf 0.12 sec without the typical QRS complex of bundle branch block. In all other subjects the intraventricular conduction time ranged from 0.06 to 0.09 sec in the vounger groups and 0.08 to 0.09 in the older. 3. Electrical Axis Deviation and Electrical Posi- tion of the Heart. There were few variations. The Table 15 Electrocardiographic Abnormalities (Percent Incidence tn Younger and Older Age Groups} Exposed Age Unexposed Age Abnormality 20-49 (24)* 250 (14) Rhythm A-V I-V RST 0 12 0 0 21 7 7 T wave 0 *Number examined. 21 Age 20-49 (55) 2 2 4 2 11 Age 250 (29) 14 3 7 14 34