es about an inch in diameter, and furnish the
_germs_ or ovules. These latter are very minute, seldom measuring 1/120
of an inch in diameter, and frequently are not more than half that size.
The ovaries develop with the growth of the female, so that, finally, at
the pubescent period, they ripen and liberate an ovum, or germ vesicle,
which is carried into the uterine cavity through the Fallopian tubes.
With the aid of the microscope, we find that these ova are composed of
granular substance, in which is found a miniature yolk surrounded by a
transparent membrane, called the _zona pellucida_. This yolk contains a
germinal vesicle in which can be discovered a nucleus, called the
_germinal spot_. The process of the growth of the ovaries is very
gradual, and their function of ripening and discharging an ovum every
month into the Fallopian tubes and uterus is not developed until between
the twelfth and fifteenth years.

This period, which indicates, by the feelings and ideas, the desires and
will, that the subjects are capable of procreation, is called _puberty_.
The mind acquires new and more delicate perceptions, the person becomes
plumper, the mammae enlarge, and there is grace and perfection in every
movement, a conscious completeness for those relations of life for which
this function prepares them. The period of puberty is also indicated by

MENSTRUATION.

The catamenial discharge naturally follows the ripening and liberation
of an ovum, and as the ovaries furnish one of these each month, this
monthly flow is termed the _menses_ (the plural of the Latin word
_mensis_, which signifies a month). The menstrual flow continues from
three to five days, and is merely the exudation of ordinary venous blood
through the mucous lining of the cavity of the uterus. At this time, the
nervous system of females is much more sensitive, and from the fact that
there is greater aptitude to conception immediately before and after
this period, it is supposed that the sexual feeling is then the
strongest. When impregnation occurs immediately before the appearance of
the menses, their duration is generally shortened, but not sufficiently
to establish the suspicion that conception has taken place. The germ is
the contribution of the female, which provides the conditions which only
require the vivifying principle of the sperm for the development of
another being. The period of aptitude for conception terminates at the
time both ovulation a