The purpose of this study was to observe the physical development of the child in housing communities called "danchi", in comparison with the child in other regions . Therefore, three groups, danchi, general urban and rural children were compared in physique and physical activities. As to physique of same children a long term observation was made over a nine-year period. It started in 1st-grade of elementary school (at the age of 6), and was repeated once a year (in April) till they graduated lower secondary school. But measurements of physical activities were carried out on 6th-grade and 9th-grade boys and girls. The major findings were the following1) Boys in danchi group is the largest in stature, body weight and sitting height and next comes the rural group and the general urban group is the smallest . But there is no difference in girls.2) In chest girth, danchi boys is inferior to rural boys in the 1st and 2nd-grade, but they surpass other group boys on and after 5th-grade.3) In relative weight, danchi boys show the largest value except 1st and 2nd-grade . In girls the value of the danchi group is lower than the rural group slightly.4) In relative chest girth, the value of danchi boys and girls is lower than that of other group boys from 1st-grade to 4th-grade. At lower secondary school period, danchi boys surpass other group boys, but in girls the ranking is in the order of the rural, danchi and the general urban group.5) Rohrer's index of danchi boys is lower than that of other group boys from 1st-grade to 3rd-grade, but at lower secondary school period the former exceeds the latter . While in girls the rural group is particularly large, followed by the general urban and the danchi group.6) Concerning physical activities, back muscle strength of the 6th-grade boys and girls in danchi shows the highest values, but at agility, flexibility, endurance and chining they are inferior to the rural group. In the case of 9th-grade, endurance and chining of danchi boys and girls are inferior to those of rural ones.
The twinning rates in 46 Prefectures of Japan were calculated from the vital statistic data in the period 1955.1959. The zygosity of twins was estimated by the Weinberg's differential method. The twinning rates increased from a low level in the southwest of Japan to a high level in the northeast. The tendency was more definite in the dizygotic twinning rate than in the monozygotic one. In old times of Japan, there had been a superstition of abhorring twin births . To investigate whether the tradition has been transmitted down to the postwar time or not, correlation-coefficients between the twinning rates of 46 Prefectures and their parameters which might affect the registration of twin births were figured out . The mediate parameters were the decreasing magnitude of the crude birth rate in the year of "Hinoe-Uma", the proportion of the delayed registrations of live births to total ones, the percent of the unlike-sexed-to total twins, and the proportion of the stillbirth-to live-birth twins . No result supported the fact that the superstition has affected the registration of twin births in the postwar era of Japan. Relationship between the twinning rate and the maternal age at birth was also analyzed during 19601967 in Japan. Although the monozygotic twinning rate seemed to have no relation, the dizygotic one showed a high maternal age dependence. The tendency was analogous to those reported in other ethnic groups. The author express his appreciation to Dr. G. Watanabe for his advice .
A medico-geographical study was made on the vital statistical data concerning three causes of death, viral hepatitis, cirrhosis of the liver and cancer of the liver from 1953 to 1972. This twenty year period was divided into four sections, 1953-1957, 1958--1962, 1963--1967 and 1968?`1972, and total deaths were obtained for each section. Standardized death rates from the three diseases were computed for all the forty-six prefectures by the indirect method using the 1960 census as their standard population, and the values were compared for geographical distribution. Coefficients of correlation between the three causes of death were also computed from the same standardized values. The results are as follows: (1) The standardized death rate from cirrhosis of the liver is higher in south-western Japan(i.e., Kyushu, Shikoku, a part of the Chugoku district and a part of the Kinki district) than in north-eastern Japan except Yamanashi Prefecture. (2) The standardized death rate from viral hepatitis, though on the decrease recently, is higher in south-western Japan than in north-eastern Japan except Fukui and Yamanashi Prefectures. (3) The standardized death rate from cancer of the liver, which shows a gradual increase in incidence, presents almost the same pattern as that of cirrhosis of the liver, being higher in south-western Japan than in north-eastern Japan except Yamanashi Prefecture. (4) The coefficients of correlation indicate that the three causes of death are closely associated with one another in terms of geographical distribution.