Fig. 2 gives a very good idea of the shape and general structure of this bony framework; while a careful study of Fig. 3 will enable one to form a very correct idea of the relative size and position of the various parts contained in this framework. ~FIG. 2. The female pelvis. The flanging sides form the hips. The union of the bones in front forms the pubic arch which is felt at the front of the lower part of the body. The lower end of the spinal column, or backbone, is seen at the back of the figure.~ =The Vagina.=--The vagina is a membranous canal extending from the surface of the body to the uterus, or womb. Its posterior wall is about 3-1/2 inches long, and its anterior about 3 inches. A careful study should be made of our illustration, in order that the relation of the vagina and uterus to the rectum behind and the bladder in front may be thoroughly understood; also the angle which is formed by the vagina and the uterus. Notice should be taken, also, of the opening of the uterus into the upper part of the vagina; as inflammation of the uterus often causes a discharge which passes into the upper part of the vagina and finally out of the body. This gives rise to the belief that the only trouble is in the vagina itself, whereas the real seat of the disease may be high up in the uterus. ~FIG. 3. A lateral view of the contents of the female pelvis. 1. the vagina; 2. uterus; 3. bladder; 4. lower bowel; 5. bone forming the pubic arch; 6. the spinal cord, with bone in front and back of it.~ =The Uterus.=--The uterus, or womb, is a hollow organ formed of muscular tissue, and lined with a delicate mucous membrane. The bladder is in front, the rectum behind, and the vagina below. =Three Parts.=--Physicians divide this important organ into three parts,--the fundus, body, and neck. The fundus is all the upper rounded portion; the body all that portion between the fundus and the neck; and the neck all the rounded lower part. =The Cavity of the Uterus.=--This is divided into the cavity of the body and the cavity of the neck. By consulting our illustration it is seen that these cavities differ greatly in shape; that of the body being triangular, while that of the neck is barrel-shaped. By referring again to Fig. 4 it will be seen that the cavity of the body has three openings, one on either side at the top going to the Fallopian tubes, and an opening at the bottom passing into the cavity of the neck. A constriction exists between these two cavities; but after childbirth this is largely done away with, and there is not that marked difference which existed formerly. =Glands in Uterus.=--In the mucous membrane lining the uterus are vast numbers of minute glands which secrete mucus. It has been asserted that in the cavity of the neck alone there are from ten to twelve thousand of these glands. It is in this mucous membrane that such remarkable changes occur each month during menstruation, and still more wonderful changes during pregnancy.