It is now interesting to observe how the uterus gradually resumes some of the pecu liar features which it exhibited at an earlier period of life, It may be said to fall back again into its infantine condition. For with the shrivelling of the ovaries, and their reduc tion to a size as small sometimes as that of a child of two or three years, (fig. 456.) the ute rus also gradually shrinks, not in all its parts, but principally in the body, or that portion which is chiefly employed in the processes of rnenstruation and gestation. This part be comes atrophied more than the rest ; its walls become thinner, partly from diminished circulation in them, and partly from atrophy of the component tissues, which appear pale and nearly bloodless. Thus it happens that, in advanced life, the walls of the uterine body, no longer possessing that fulness which at an earlier period caused them to encroach upon the cavity, and to exhibit that incurvation of the sides and fundus which has been described as characteristic of the mature organ, again re turn to the straight and more attenuated con dition mhich they had in early life. We may often observe, therefore, in the uterus of aged persons, a nearer approach to the form of the equilateral triangle, caused by the short ening of the body and the straightening of its walls, than is seen in the uterine cavity of mid life ; and it is this return to the form of the fcetal cavity, together with the now derating size of the cervix, uhich remains nearly unchanged, that gives to the aged ute rus its greatest similitude to that of infancy or early youth.
But these changes are not limited to the body of the uterus. The external uterine orifice being now no longer required to serve as a conduit for fluids to or from the uterus, or for the passage of more solid contents, becomes reduced in diameter, and may some times be observed to possess an aperture that would hardly admit the head of a mo derate sized probe.
The uterus, in common with the rest of the generative organs, being concerned only in the reproduction of the species, its offices are limited to that period in which the animal functions are maintainea in their highest state of efficiency. The growth of the body is nearly or quite completed before the sexual offices commence, and the power of reproduction continues as long as the frame is maintained in full vigour ; but when the age arrives at which the animal func tions generally begin to decline, their de cay is anticipated by the total cessation of the power of procreation in the female. The period, therefore, is limited, yet not brief, during which the functions of the uterus can be exercised, and on either side of this epoch the organ remains passive, except under ab normal states.
The chief functions of the uterus are those which relate to — 1. Menstruation ; 2. In semination ; 3. Gestation ; 4. Parturition.
The office of the uterus in nzenstruation. — Although the uterus is the efficient instrument in the performance of menstruation, yet the power of initiating and regulating this function resides in the ovaries, which exert a powerful reflex influence, not only upon the uterus, but also upon the entire organism. Without the ovaries, menstruation has never been known to occur. Their artificial removal is followed by a permanent cessation of the catamenial flow, although the uterus may be left unin jured ; while the congenital absence of both ovariesis always accompanied by an enduring amenorrhcea.
The external sign or evidence of menstrua tion consists in the occurrence of a sanguine ous discharge, which escapes from the vaginal orifice of women in health, periodically, except during pregnancy and lactation. This dis charge first appears usually between the four teenth and sixteenth years, and continues to be repeated at intervals of a lunar month for an average period of thirty years. The time, however, of the conimencement, as well as of the decline, of menstruation is very variable, and may be either much accelerated or re tarded, according to individual peculiarities.* Periods of duration and The catamenial period and interval together occupy a space of one lunar month. And in some women this function is performed with such regularity that the day, and very nearly the hour, of its expected return may be predicted. The natural duration of the flow varies from three to five or even seven days. An interval then occurs during which the flow entirely ceases. This occupies from twenty-one to twenty-five days ; and it is during the first half of this interval that conception most com monly takes place.
It cannot, however, be asserted that this degree of regularity is observed even in the majority of women. Frequently the period of regular return is anticipated by one or more days ; or, on the other hand, it may be re.. tarded, without the occurrence of any con comitant disturbance of other functions, such as would justify the regarding of these ex amples as abnormal. But whatever may be the amount of variation — dependent in most cases upon idiosyncrasy, — still a law of pe riodicity is observed which, in all ages and countries, has been recognised, and more or less distinctly expressed by such terms as catamenia, menses, courses, periods, regles, mois, monatlicher Fluss, and the like.
No catamenial discharge takes place nor mally during pregnancy or lactation. Excep tions to both these rules, however, occur, and instances of the latter are sufficiently common. But with regard to the former, it is probable that many at least of the recorded cases of menstruation during pregnancy have been cases in which the placenta was implanted low down, or even over the os, under which circumstances it is well known that slight flooding will occasionally commence at an early period of gestation, and observe a cer tain rough periodicity. Upon anatomical grounds, a catamenial flux during pregnancy can only be supposed possible where the con dition of the uterus is such as to admit of the discharge taking place from the vaginal portion of the cervix ; an occurrence which is shown by Mr. Whitehead to have obtained in all the instances of supposed menstruation during pregnancy which he had investigated. For " on examining these cases with the speculum during the existence of the menstnial pheno mena, the blood was invariably found issuing from diseased surfaces situated upon or about the labia uteri, none escaping from the interior of the organ."* But in any case there is wanting a sufficient series of observations, taking cognisance of the exact duration and times of recurrence of such discharges, and comparing these with the normal periods and intervals of menstruation, to warrant an unhesitating belief in the occur rence of a true catamenial flow as a possible phenomenon during gestation.