=The uterus=, or womb, in which the baby develops, is a firm little mass of muscle, which, in its non-pregnant state, is much the shape of a slightly flattened pear, about three inches high, an inch and a quarter wide at its broadest point, three quarters of an inch thick, and weighs about two ounces. We usually speak of the main part of the uterus as the _body_: the round top as the _fundus_ and the smaller part of the organ, below, as the neck or cervix. This important little organ is placed about the middle of the true pelvis, with the upper end pointing slightly forward. (See Fig. 2.) It is more or less swung in this position by being attached to ligaments instead of to any fixed part, the ligaments, in turn being attached to the sides of the pelvis. This explains why the uterus may move about, tip forward or backward, and how, by a stretching of the ligaments that hold it, it is able to grow and push upwards as pregnancy advances. Within the body of the uterus is a flat cavity which is somewhat triangular in shape, with an opening at each of the three corners. The two upper openings lead into the tubes, which will be described in a moment, while a third opening leads down into the cervix, the lower end of the cervix, in turn, protruding into the vagina. The upper and lower ends of the cervix are drawn in as though with a draw string so that they are scarcely more than small round holes. These are called the _internal os_ and the _external os_. Fig. 3 gives an idea of how the cavity of the uterus and the cervix would look from the front, with the tubes reaching out from the upper corners of the uterus, and the cervix opening into the vagina. The uterus is lined with a soft mucous lining something like the lining of one’s mouth. Bear this in mind, for this lining represents, in part, the soil in which the tiny human seed is planted and through which its roots draw nourishment. =The Fallopian tubes= are two little muscular passage ways, about five inches long, which extend from the two upper corners of the uterine cavity toward the sides of the pelvis. The tubes are very small where they arise from the uterus, but gradually grow larger toward their free ends and finally spread out into wide, funnel-shaped openings that lead directly into the abdominal cavity. The tubes, also, are lined with a mucous membrane but of a most surprising kind. Its surface is covered with tiny hair-like projections which make it something like a brush with very soft, moist bristles. These little hairs are in constant motion, waving and sweeping along in much the same way that a field of wheat waves and sweeps in the wind. Remember about this, too, for it has something to do with the very beginning of the baby. [Illustration: FIG. 3.—Diagram showing the structure and relation of the female generative organs, as seen from the front. ]