cessation depends
somewhat upon the date of its first appearance. In the temperate zones
it commences at about the fifteenth year, and, consequently should
terminate at the forty-fifth year. Instances are common, however, in
which it has been prolonged until the fiftieth and even to the
fifty-fifth year. In warm climates it commences and terminates at an
earlier age.

As women approach the critical period of life, if the general health and
habits be good, the discharge may gradually diminish, and, at length,
totally disappear, without producing any particular inconvenience, but
this seldom happens. More frequently, the discharge is entirely absent
for six or seven weeks, and when it does return, it is more copious than
usual. In some cases, the flow is not only too profuse, but too
frequent. Many months may elapse before the menses return, and, even
then, they are apt to be very pale and deficient in quantity.

The fluctuations of this function occasion irregularities and
disturbances of the general health. When the flow of blood is diverted
from the uterus, it is liable to be directed to the head or some other
part of the body. In fact, there appears to be constitutional agitation,
and disorders of all the organs. Perhaps one reason for calling this a
critical period is, that if there is a morbid tendency in the system, a
disposition to develop tumors of the breast or uterus, these are very
liable to make rapid progress at this time, since they are not relieved
by the customary, local exudation of blood. It is a time favorable to
the awakening of latent disorder and morbid growths, for, at the decline
of the menstrual function, the uterus is not so capable of resisting
vitiating influences.

There is greater liability to irritation of the bladder and rectum, and
the menstrual flow may be superseded by a white, acrid discharge, caused
by an inflammation of the mucous membrane of the vagina. Even if the
system be not enfeebled by excessive losses of blood, debility may
result from a continued irritation of the uterine organs, and cause the
morbid discharge. The nervous system sympathetically responds, becoming
exceedingly irritable, and thus implicating in this derangement every
bodily organ. In some constitutions, the change of any habit is almost
impossible, particularly if it is improperly acquired, or detrimental to
health; and so we have sometimes thought respecting this function, that
the more it has been abuse