Since the 1920's, there has been a slow fluctuating upward trend in primary sex ratio (ratio of males to females at birth) in Japan. The factors :concerned with the rise of sex ratio have been analyzed by using the vital statistics and other data for the period from 1947-1969. There is no evidence indicating that the age of the mother or the birth order are contributing factors causing an increase in the ratio. The recent decrease in still birth rate suggests a possible relation with the increase of the sex ratio at birth. Provided that the ratio of the number of still births to that of live births were the same in the periods of 1955-64 and of 1965-69, the extent to which the sex ratio at birth in 1955-64 would be modified was calculated. By this calculation, the modified sex ratio at birth in 1955-64 was 106.2, in contrast the actual value was 105.8. The correlation between the sex ratio at birth and some social indices by prefectures has been examined in the respective periods of 1960-64 and 1965-69. For both periods, signifi cant correlation coefficients were obtained between the sex ratio at birth and the rate of hospitalization at delivery. Only in 1960-64, social indices as the percentage of employed persons in primary indust ries to total employees, the "MYNRYOKU" index (synthetic index of socioeconomic indices) and the percentage of women workers to total employees were significantly correlated with the sex ratio at birth by prefectures.
From the results of the investigations of 148 patients afflicted with mental alienation in our national sanatorium situated in Nagoya City, 12, 600 patients abstracted from all the forced patients in Japan and 10, 539 patients in all the lunatic asylums in Kanagawa Prefecture, the following conclusions were drawn. 1) By age-group, of the 148 patients in our national sanatorium those of 20's stand first in number (45.3%) and those of 30's stand second (20.9%), while of the 12, 600 forced patients those of 30's stand first (35.3%) and those of 20's stand second (23.2%). And of the 10, 539 patients in Kanagawa Prefecture those of 30's stand first (35.3%) and those of 20's stand second (23.6%). As stated above, young age-groups, 20's and 30's, have more sufferers in Japan, while the aged group above 65 years has more sufferers in foreign countries, a striking contrast between the two. Accordingly, we presume that aged sufferers from mental alienation will increase in Japan, too, in future with the aging of our population. 2) By sex, of the patients in our sanatorium 79 are male and 69 are female (=100 : 87.3) ; of the forced patients 7, 721 are male and 4, 879 are female (100: 63.2) ; of the patients in Kanagawa Prefecture 6, 067 are male and 4.472 are female (=100 :73.7). Namely, there are more male sufferers than female ones in Japan, while there are more female sufferers in foreign countries. In this, Japan is, as it were, antipodal to them. 3) Of the psychoses, schizophrenia is most prevalent, from which 63.5% of the patients in our sanatorium, 77.6% of the forced patients and 67.2% of the patients in Kanagawa Prefecture are suffering. 4) From the hereditary point of view, only 6.8% of the patients in our sanatorium and 10.8% of the new patients in the whole country come of psychopathic stock. But this rema ins to be investigated more minutely. 5) The result of clinical examination is that as many as 33.1% of the patients in our sanatorium ire sufferers from an impediment in liver function. This is probably due to administration of too much psychotropica. How to cope with this: 1) to strengthen and establish the structure of local medical facilities. 2) to enforce and promote the rehabilitation system. 3) to consolidate special hospitals and send specialists to mental hospitals.
Seventy-four women living on Kuchinoshima in July 1969 were interviewed for their histories of marriage, pregnancy and delivery. They became to have a small size of family year by year like the general trend in Japan, but the number of children wanted and perfor med by the women on Kuchinoshima was constantly larger than that observed on the group of the same age-cohort and similar occupations in Japan. Substantially, the length of marital life within reproductive age was significant for the number of live-births, and the early age of marriage was an auxiliary factor for their high fertility rate.