The differential diagnosis between uterine fibroid and ovarian cyst is easy except in the case of the fibro-cystic tumor. Such tumors have very often been mistaken for ovarian cysts. The mistake is not at all serious, as celiotomy is indicated in either case. The operator, however, should always determine the nature of the tumor before proceeding with the operation after the abdomen has been opened, as puncture of a fibro-cystic tumor may be attended by alarming hemorrhage. A small fibroid in the posterior wall of the uterus has often been mistaken for retroflexion, and the woman has been treated with a pessary. This mistake may be avoided by feeling, with the abdominal hand, the fundus uteri in its normal forward position, or by determining the true direction of the uterus with the uterine sound. The =prognosis= of uterine fibroids may be determined from a consideration of the natural history, the degenerations, and the complications of these neoplasms, which have already been described. Fibroid tumors are benign growths, in contradistinction to cancer and sarcoma. They do not infiltrate contiguous structures or invade the general system; but they are not benign in the sense that they are not dangerous to life. As has been said, the disease may terminate as a uterine polyp, which may be discharged from the body. But during this process the woman may die from hemorrhage or from septic absorption from the sloughing, disintegrating tumor. Some unusual fibroids give no trouble whatever, never attain a large size, and are discovered only accidentally during the life of the woman or at the autopsy. In very exceptional cases--so rare that they are to be looked upon as medical curiosities--the fibroid disappears spontaneously even after it has reached a large size. This has occurred as the result of an accident, exploratory celiotomy, and pregnancy. We have no right in any case, however, to look for such favorable termination. The accidents that may happen to the tumor itself, and which imperil the life of the woman, are various and occur frequently. The dangerous forms of degeneration--the edematous, the cystic, the telangiectatic, and the sarcomatous--occur with sufficient frequency always to be dreaded; and, even though these dangers be avoided, the anemia from the continual hemorrhage exposes the woman to fatal results from the diseases and accidents of daily life. The most favorable course that we have a right to expect, in any case of fibroid tumor of the uterus that is not discharged as a uterine polyp, is that it will grow slowly, that it will produce symptoms not unendurable, and that at the menopause it will cease to grow and will atrophy or disappear.