The foetus at the end of the eighth week is about one inch in length; at the end of the fourth lunar month it is from four to six inches long, and its sex may be distinguished. At the end of twenty-four weeks, if the normal foetus is born it will attempt to breathe and to move its limbs, but it dies in a short time. At the end of twenty-eight weeks of gestation if it is born it moves its limbs freely and cries weakly. It is nearly fifteen inches in length and weighs about three pounds. Such an infant might be deemed viable, but its chances for life are extremely precarious, even in most expert hands and with the help of an incubator. At the end of thirty-two weeks of gestation a foetus if born may be raised with skilful care, but the chances are not promising. It is viable. At the end of forty weeks the child is at term. In 1876 Parry collected 500 cases of extrauterine pregnancy from medical literature, but when Tait in 1883 first operated on a case of ruptured tubal pregnancy attention was called to the subject. It was better understood as coeliotomies (opening the abdomen) became common, and in 1892 Schrenck collected 610 cases that had been reported during the preceding five years. Küstner alone has operated on 105 cases in five years. There has been much discussion among physicians as to the causes that arrest the fertilized ovum in the tube, but whatever these causes may be they do not affect the moral questions which come up in this article. There may be mechanical obstruction from peritoneal adhesions, or abnormal conditions resulting from inflammatory diseases of the tubes, ovaries, and the pelvic peritoneum, but no general cause that will explain all cases can be ascribed. {5} Tait denied the possibility of Ovarian Pregnancy, or a pregnancy where the ovum fastened to the ovary itself and developed there, but five fully established cases of this kind have been reported. Dr. J. Whitridge Williams, professor of Obstetrics at the Johns Hopkins University, in his textbook on Obstetrics (New York, 1903), collects twenty-five cases of ovarian pregnancy, where five cases are certain diagnoses, thirteen highly probable, and seven fairly probable. In these twenty-five cases ten foetuses reached full term, but four of the five certain cases ruptured at early periods. It was formerly thought that primary abdominal pregnancy is quite common; that is, that the ovum is implanted on some organ within the abdomen itself, apart from the uterine adnexa. This is now looked upon as very doubtful, and such cases are probably secondary; that is, secondary to a pre-existing tubal pregnancy which has ruptured without great maternal hemorrhage and let the foetus grow within the peritoneal cavity.