If the gestation has advanced beyond the fourth month, it is often impossible to remove the placenta without fatal hemorrhage. Many women have bled to death from the attempt. The operator sometimes incises the placenta as he enters the gestation-sac, and is obliged to proceed with its removal. In other cases he starts to remove it, and finds, too late, that the hemorrhage is beyond his control. In the advanced months of pregnancy the sac and the placenta may become adherent to any of the abdominal or pelvic viscera and to the large vessels. Hemorrhage cannot be controlled, as in the earlier months, by ligation of the ovarian and uterine arteries. The result in these cases is determined by the ability of the operator. A full-term living child, the whole sac, and the placenta have been successfully removed. If the attachments are such that the surgeon considers it unsafe to attempt the removal of the sac and the placenta, the sac should be incised and the fetus should be removed, the cord being divided between two ligatures; the sac should be sutured to the abdominal incision; the cord should be drawn through the opening, and the sac packed with gauze. At the end of four or five days the gauze pack may be removed, under anesthesia if necessary, and the placenta may be taken away. There is very much less risk of hemorrhage after the lapse of a few days. Some operators prefer to allow the placenta to come away spontaneously. This is sometimes necessary. It will be seen, from this consideration, that the treatment of all varieties of ectopic gestation is operative, and that the sooner the operation is performed the better for the patient. Consideration for the life of the child should have no influence in determining the time of operation. =Ovarian Pregnancy.=--The possibility of the implantation and development of the fertilized ovum in the Graafian follicle has been denied by many authorities. It seems probable, however, that such a form of pregnancy does very rarely occur. The cause of ovarian pregnancy is thought to be due to some disturbance of the normal process of ovulation, whereby the ovum fails to leave the ruptured follicle and is there fertilized and developed. CHAPTER XXVII. DISEASES OF THE OVARIES. =Anatomy.=--The ovaries vary a good deal in size, within the limits of health, in different individuals. It is unusual to find the two ovaries in the same person exactly alike in size, shape, and appearance. [Illustration: FIG. 158.--Uterus, tube, and ovary of a child one month old (Sutton).] The size, shape, and appearance of the ovary change at the different periods of life. In the new-born child the ovary is elongated and lies parallel to the Fallopian tube (Fig. 158). In rare cases this infantile shape of the ovary may persist throughout life.