23 ‘ranged from 20 to 26 months, with an average of 22.4 months. To determine whetheror not somepattern 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 two trends. First, the weight rankings corresponded to chronological age rankings andnotto statural rankings. Second, the lack of synchrony in rankings of several measurements was noticeable in those children who were shorter than their youngersibs. This con- trasted 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 obser- vations that these children were exposed to radia- tion at a particularly vulnerable age and that the resulting retardation in osseous developmentled 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 abnormalities are included for 1960 in the unexposed group because this group was not examined in the 1960 survey. This table does not show any significantdifferences between the abnormalities noted in the exposed andin the unexposed populations. Results of special examinationsare discussed below. CARDIOVASCULAR SURVEY The cardiovascular findings may be foundin the table of physical abnormalities (Table 14). The incidenceof 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, amongthe younger group 15% had one or more abnor- malities, and in the older group 41%. Specific findings may be summarizedasfollows. 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 occurredin 3 of 14 exposed individuals andin 4 of 29 unexposed. 2. Conduction Times. Few abnormalities were seen. No individualin either the exposed or the unexposed group had prolonged auriculoventricular 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 prolonged in several subjects. In the younger unexposed group, the ORSinterval 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 prolonged to 0.12 sec in only one individual, age 81, who had a marked degree of hypertensive and arteriosclerotic cardiovascular disease and cardiac enlargement. Among29 individuals in the older unexposed group, two showed intraventricular conduction timesof 0.12 sec withoutthe 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 younger groups and 0.08 to 0.09 in the older. 3. Electrical Axis Deviation and Electrical Position of the Heart. There were few variations. The Table 15 Electrocardiographic Abnormalities (Percent Incidence in Younger and Older Age Groups) Exposed Abnormality Rhythm A-V I-V RST T wave Unexposed Age 20-49 Age 230 0 21 (24) 12 0 0 0 *Number examined. (14) 7 7 7 21 Age 20-49 (55) 2 2 4 2 11 Age 290 (29) 14 3 7 14 34