mucous membrane, the soil, as it were, in which the ovum is planted.
We must now learn how the maternal tissues assume the responsibility
placed upon them.

THE REACTION OF THE UTERUS.--The womb, which is small before
marriage, is converted by pregnancy into the largest organ of the
body. The virginal uterus, shaped somewhat like a pear, and placed
with apex downward, is carefully protected within the bony basin
between the hips, which is commonly called the Pelvis. The upper and
larger part of the organ, known as the body, lies at the bottom of
the abdominal cavity; the lower part, the neck, projects into the
vagina. The cavity inside the womb communicates above with the two
oviducts and terminates below in a canal which runs through the neck
and opens into the vagina by an orifice known as the mouth of the
womb.

Pregnancy modifies every portion of the womb in one way or another;
but the most profound alterations occur in the body, in the cavity of
which the ovum has come to rest. During the forty weeks of gestation
the organ grows in weight from two ounces to as many pounds; from
three inches in length it increases to fifteen inches; and its
capacity is multiplied 500 times.

The mucous membrane which lines the cavity of the uterus responds to
the stimulus of pregnancy in a characteristic manner and with a
single purpose, namely, to promote the development of the ovum. In
connection with menstruation we noted that this membrane periodically
prepares for the reception of an ovum. And if the expected ovum has
been fertilized, its arrival is followed by arrangements for its
protection and nutrition which are far more elaborate than the