The opposite state to menarche praecox is that in which the first appearance of menstruation is unduly delayed; it may be even till after the age of twenty. Such a postponement of the menarche sometimes occurs in girls who exhibit at this period of life an extraordinarily great general fatty development of the body, or a notably severe chlorotic state of the blood, or in whom during the years of development some sudden and extensive change in the mode of life has occurred, as for instance when the girl’s place of residence has been removed from the country to the town, or when she has had to undertake some completely new kind of physical or mental work. _Raciborski_ attributes the late appearance of menstruation, at the ages of 20, 22, 24, or 26, in otherwise healthy girls, to an “apathy of the sexual sense,” a phrase which does not convey much meaning. According to _Marc d’Espine_, puberty occurs early in girls with dark hair, grey eyes, a delicate white skin, and of a powerful build; late, on the other hand, in girls with chestnut hair, greenish eyes, a coarse darkly-pigmented skin, and of a delicate weakly build. The genitals of girls in whom the first appearance of menstruation is delayed, frequently exhibit distinct signs of the backwardness of the reproductive organs in their development. The external genitals, in such cases, have little if any covering of hair, and are flabby and relaxed; the body and the fundus of the uterus are shorter and more slender than usual, the uterus as a whole is small and flaccid, sometimes anteflexed; the vaginal portion of the cervix is small, often almost undeveloped, its anterior lip barely projecting above the surface of the vaginal fornix; the vagina is usually short and narrow. The ovaries also are flaccid and inelastic, and occasionally are remarkably small. The breasts are small, the nipples and areolæ undeveloped. In other cases, notwithstanding the delay in the appearance of the menarche, the genital apparatus is developed to a degree quite in correspondence with the age, but some pathological condition is present, for instance, the mucous membrane secretes excessively, exhibits a catarrhal tendency, there are erosions at the os uteri, etc. PATHOLOGY OF THE MENARCHE. A series of disturbances of function and pathological changes in the organs may occur at the time of the menarche, either directly connected with the genital organs, or etiologically dependent upon the changes occurring in these organs.