As a rule, fibroid tumors of the uterus are of slow growth. In some cases five, ten, or fifteen years may elapse before the tumor attains the size of the fetal or the adult head. Sometimes the tumor appears to be of limited growth, and early attains its maximum size, or it may not increase at all in size after its first discovery by the woman; in other cases the tumor slowly but steadily grows until, after a lapse of ten or twenty years, it fills the whole of the abdominal cavity and renders the woman helpless from weight and pressure; and, finally, in some instances the tumor grows unlimitedly with the rapidity characteristic of an ovarian cyst, and in one or two years may crowd the woman out of existence. This rapid unlimited growth is characteristic of tumors of the fibro-cystic variety. A fibroid tumor causes very marked changes in the body of the uterus--the muscular coat and the endometrium. The whole uterus becomes enlarged. The cavity is increased in length, and the muscular wall becomes often very much hypertrophied. This hypertrophy resembles that occurring in pregnancy. Even small fibroid tumors may produce this condition, which seems to depend more upon the position than upon the size of the growth. The interstitial and the submucous tumors are accompanied by a greater degree of uterine hypertrophy than accompanies the subperitoneal growths. In some cases the uterus may be of normal size if the subperitoneal growth has become pedunculated. The uterus may appear to be uniformly enlarged to the size of the fourth or fifth month of pregnancy, and when incised it will be found to contain one or more interstitial or subperitoneal tumors that have become encapsulated by it. When such a case is subjected to celiotomy the resemblance of the uterus to pregnancy is very striking. Between such a smooth, uniformly enlarged uterus on the one hand, and the irregular, distorted mass of subperitoneal fibroids on the other, there are an infinite number of varieties. A great increase in the vascular supply accompanies the hypertrophy of the uterus. The ovarian and uterine arteries and their branches become very much hypertrophied, while the veins in the broad ligaments and the sinuses in the capsule of the tumor become enormous. The endometrium shares in the changes that take place in the uterus. It is, of course, increased in area with the increase of the uterine cavity. There may be atrophic changes from pressure upon or tension of this membrane, or various forms of endometritis may be present, most usually the interstitial and the glandular. The glandular form of the disease is said to occur most frequently when the tumor is remote from the cavity of the uterus, as in the subperitoneal variety; while interstitial endometritis occurs with the submucous and the interstitial tumors.