These cases are often mistaken for cancer of the body of the uterus, and the diagnosis should always be immediately made by microscopic examination of the material removed by a thorough curetting of the whole of the uterine cavity. The treatment of senile endometritis consists of applications to the endometrium of a solution of nitrate of silver, from one-half to one dram to the ounce of water, or of thorough curetting of the endometrium. CHAPTER XVIII. SUBINVOLUTION OF THE UTERUS; SUPERINVOLUTION OF THE UTERUS. SUBINVOLUTION OF THE UTERUS. Subinvolution of the uterus is a condition that results from imperfect involution of the uterus after labor, abortion, or miscarriage. The muscular and fibrous structures of the uterus, which had become hypertrophied under the influence of pregnancy, fail to undergo properly the retrograde changes of fatty degeneration and absorption which normally occur after the expulsion of the product of conception, and which are essential for the restoration of the uterus to its normal size. The elements of the endometrium and the vascular system of the uterus also remain hypertrophied; consequently the uterus is larger, heavier, more congested than normal. Similar arrest of involution may occur coincidently in the ligaments of the uterus, which are left larger, longer, and more relaxed than in the normal condition. The pathological changes that occur in the subinvoluted uterus are similar to those found in chronic endometritis and metritis, which have already been described. In fact, chronic endometritis and metritis accompany subinvolution from the beginning. There are many causes of subinvolution of the uterus. Too early rising from bed is a most frequent cause. This is especially true after abortion or miscarriage; for many women treat such occurrences as of but little moment, and refuse to stay in bed for more than a few days. Imperfect evacuation of the uterus after abortion or miscarriage is a common cause. Laceration of the cervix, retrodisplacement of the uterus, and laceration of the perineum are all causes of subinvolution of the uterus. The symptoms of subinvolution are the same as those already described under Chronic Metritis--backache, headache, bearing-down pain in the pelvis, general physical debility, leucorrhea, and menorrhagia. The =treatment= of subinvolution should be directed toward the relief of the primary cause of the condition. Laceration of the perineum or of the cervix, retroversion, or endometritis caused by retention of placental tissue after miscarriage, should receive appropriate treatment. Subinvolution may often be cured by the douches, iodine applications, and depletion of the cervix spoken of under the treatment of laceration of the cervix, provided the primary cause is removed or corrected.