One of the most remarkable properties of the Womb is that of being able to distend to an extraordinary degree, and then retract again to nearly its original size. The force which it sometimes exhibits during its contraction is very great, being sufficient to separate, and even break, the bones of the mother's pelvis, and paralyze the hand of the operator when introduced. The Muscular Fibres on which this contractile force depends are most obvious during gestation; they then appear very numerous, and very curiously disposed, some of them ramifying in almost every direction, as will be seen by Plates V, VI. It is owing to this that the Womb contracts in every conceivable direction, and thus presses, during labor, on every part of the child's body. PLATE V. Figures 1 and 2. Fig. 1. In this plate represents the Muscular Fibres a little exaggerated, so that they can be more distinctly seen.--_a. a._ are the orifices of the Fallopian Tubes. Fig. 2. Represents the natural appearance, the fibres not being quite so distinct, though sufficiently obvious.--_a. a._ The orifices of the Fallopian Tubes. In both Figures the Womb is supposed to be turned inside out, its peculiar structure being more readily seen interiorly than exteriorly. [Illustration: Plate V. The Muscular Fibres of the Womb.] PLATE VI. Figures 1 and 2. Fig 1. This represents the appearance of the Fibres externally, and shows how they terminate in the round ligament a. b. Fig. 2. The lines _a. b._ represent the direction of the force of the Fundul Fibres; _c. d._ That of the Circular Muscles of the body of the Uterus; _d. e._ The combined force of the Muscles. The dotted lines represent the force reflected by the liquor amnii. The dotted curved lines the direction of the circular fibres of the body of the Uterus. [Illustration: Plate VI. The Muscular Fibres of the Womb.] THE VAGINA. The Vagina (_c._ Plate I.) is a membranous canal, lined with a mucus membrane like the Uterus. By its upper part it is attached to the neck of the Womb, at about two-thirds of its height--so that two-thirds of the neck hang within the Vagina. Below, it terminates in the Vulva, or external mouth. The upper part of the Vagina is much larger than the lower part, particularly in those who have borne children. It is capable of considerable distension, and after retraction, to allow of the child passing down it from the Womb. The external mouth is called the _Vulva_, and is usually partly closed, in the virgin state, by the membrane called the Hymen, (_n._ Plate I.) The length of the Vagina is from three to five inches, and its diameter from one inch to one and a half, or even two inches in those who have borne many children. THE VULVA.