“_Third Month._—The embryo weighs from three hundred to four hundred grains, and measures from two and a half to three and a half inches in length. The forearm is well formed and the fingers are discernible. The umbilical or navel cord is about two and a half inches in length. The head is relatively large, the neck separates it from the trunk, and the eyes are prominent. The chorion has lost most of its villi, and the placenta is formed. Points of ossification are present in most of the bones. Thin membranous nails appear on the fingers and toes. Sex may be determined by presence or absence of the uterus. “_Fourth Month._—The fœtus weighs five or six ounces, and is about five inches long. Its sex is more distinct; movements are visible. The convolutions of the brain are beginning to form: ossification is extending: the placenta is increasing in size, and the cord is about twelve inches long. The head is one-fourth the length of the whole body. The sutures and fontanelles are widely separated. Hair begins to appear on the scalp. If born, the fœtus may live three or four hours. “_Fifth Month._—Fœtal weight has increased to ten ounces, and length to about nine inches. The head is still relatively large. Fine hair, (lanugo) appears over the whole body. Fœtal movements can be felt by the mother. If born the fœtus can live but a few hours. “_Sixth Month._—Weight about twenty-four ounces, length eleven inches. Fat is found in the subcutaneous cellular tissue. Hair is darker and more abundant. The membrana pupillaris exists but the eyelids separate. If born at this time the fœtus breathes freely, but life is retained only a few hours, with rare exceptions. “_Seventh Month._—Weight from three to four pounds, length fourteen to fifteen inches. The skin is wrinkled, of red color and covered with vernix caseosa. The pupillary membrane disappears. If younger than twenty-eight weeks it is not likely to live. “_Eighth Month._—Weight from four to five pounds, length from sixteen to eighteen inches. Development is now rather in thickness than length. The nails are nearly perfect, and the lanugo is disappearing from the face. The navel is gradually approaching the centre of the body, until now it has nearly reached the median point. The cranial bones are easily molded under pressure, a point to be remembered as bearing on the question of induced labor in pelvic deformity. “_Ninth Month_—or at term.—At the end of pregnancy the fœtus weighs an average of six and a half or seven pounds, and measures about twenty inches in length. The average weight of mature males is greater than that of females. At birth the fœtus is covered with vernix caseosa, a whitish tenacious substance, composed of a mixture of surface epithelium, down and the products of sebaceous glands. During intra-uterine life it serves as a protection for the skin against the amniotic fluid. It can be removed thoroughly only by preceding the use of water by a free use of oil.”