Data from this study support the View that the following factors are not sufficiently important in Korea to invalidate the relationships observed between age of marriage and fertility: (1) Premarital pregnancy and common law marriage, (2) shortening of birth intervals in late marriages, (3) adverse effects of very eary marriage in reproductive capacity, and (4) postponement of first pregnancy among early marriages. Thirteen variables which were considered to be potential predictors of fertility were studied to determine their influence on three indices of fertility. Age of marriage and family planning praetice are the strongest predictors and account for about 10% and 7% of the total variance, respectively. Seven other factors each account for an intermediate amount of variability; these are ideal number of children, rural versus urban study area, education, aspiration for daughter, index of exposure to mass media, economic index of respondent's home at survey, and residence before marriage. The remaining variables have no consistently significant relationship to fertility. Most of the relationships appear to be stable and consistent over time; others appear to be changing. The latter group include those variables which are associated with modernization indices of family planning practice, mass media exposure. and aspiration for daughters. Thus, the index of family planning practice is of limited significance for the $40{\sim}49$ age group but is the most important variable for the $20{\sim}29$ year women. The relationship is a direct one for the two age groups between 30 and 49 years which suggests that these groups already had high fertility when family planning services became available and that this high fertility then became an inducement to acccept contraception. The pattern of relationship is not yet clear for the $20{\sim}29$ year group. Similar interactions are observed for the other indices of modernity and are discussed. The thirteen variables together can account for a maximum of about 40% of the variance in the number of live births in the age group $30{\sim}39$, and for lesser amounts of variance in other age and fertility groupings.

생쥐(C3H/JMS)의 한쪽 자궁(子宮)에 봉합계(縫合系)를 삽입한 후 초기배아(初期胚兒)의 발생과정(發生過程), 이동속도(移動速度) 그리고 착상(着床)의 상태를 관찰하였다. 임신한지 2일째 되는 날에 자궁(子宮)에 장치를 받지 않은 쪽에서는 초기배(初期胚)의 일부가 이미 수난정(輸卵精)의 뒷부분에 도달하고 있었으나 장치를 받은 쪽에서는 아직도 수난정(輸卵精) 중부(中部)에 머물러 있었다. 3일째가 되면 대조(對照)가 되는 바른쪽 자궁(子宮)에서는 $8{\sim}16$세포기에 드는 배아(胚兒)가 79%에 이르며 24%는 이미 자궁(子宮)에까지 도달하고 있으나 장치를 한 쪽에서는 $8{\sim}16$세포기의 배아(胚兒)가 69%가 되며 겨우 8.2%만이 자궁(子宮)에 이르고 있다. 4일째가 되면 대조자궁(對照子宮)에서는 전체 배아(胚兒)의 75%가 그리고 장치 자궁(子宮)에서는 61%가 상실배(桑實胚)를 이루며 전자(前者)에서 60%, 후자(後者)에서는 40%가 자궁(子宮)내에 진입하게 된다. 정상적(正常的)인 생쥐에서는 임신 4일이 되면 거의가 배낭기(胚囊期)에 이르는 것으로 알려져 있으나 한쪽 자궁(子宮)에 실을 장치한 생쥐에서는 대조자궁(對照子宮)이거나 장치 자궁(子宮)이거나 모두 배낭(胚囊)의 형성(形成)이 늦어지고 있다. 한 자궁(子宮)당 발견되는 정상배(正常胚)의 평균치(平均値)는 대조구(對照區)에서 6.3정도로 임신 2일에서 4일 사이에 큰 차이가 없으나 처리구(處理區)에서는 2일에서 4일 사이에 6.5에서 3.8로 감소한다. 이상배(異常胚)는 대조구(對照區)에서 2일째에 2.2였던 것이 0.4로 크게 줄지만 처리구(處理區)에서는 대조구(對照區)에서 처럼 급격한 감소를 볼 수 없다. 임신한지 17일 되는 날 대조구(對照區)에서 15개의 자궁(子宮)가운데 한지 2개의 자궁(子宮)만이 착상(着床)흔적을 보였지만 처리구(處理區)에서는 전혀 착상(着床)되었던 흔적을 볼 수 없었다. 결국 생쥐에서는 한 쪽 자궁(子宮)에 이물질(異物質)을 삽입했을 때 장치를 받은 자궁(子宮)뿐 아니라 다른 한 쪽 자궁(子宮)에서도 착상(着床)이 일어나지 않을 뿐 아니라 이상난자(異常卵子)의 발생(發生)을 증가시키며 배아(胚兒)의 난할속도(卵割速度)가 늦어지고 또 배아(胚兒)의 이동(移動)이 늦어진다는 것을 알게 되었다.

In the present studies, effect of progesterone on the germinal vesicle break-down of the mouse oocytes cultured in the micro tube was investigated. The results obtained are as follows: As dose of progesterone in the medium rose, accordingly the break-down of the germinal vesicle was suppressed. It was found that $ED_{50}$ was 15.7 ${\mu}g$/ml, and $ED_{90}$ 60.7 ${\mu}g$/ml of progesterone. The dose suppressing the oocyte maturation was apparently higher than that on the rabbit or on the mouse embryonal development. The inhibiting effect of progesterone on the GVBD was reversible. The germinal vesicle of the oocytes were broken down immediately in the medium upon removal of the hormone. Progesterone stops meiosis at any stage upon administration, while dbe AMP or theophylline supresses only the break-down of the nuclear membrane. Recovering of the meiotic division of the oocytes once exposed to progesterone was delayed a little. The inhibiting action of progesterone was not altered by adding more pyruvate or in the presence of higher concentration of the mineral ions in the culture medium.