running sinuously from its upper angles out towards the side of the pelvis (Figs. 22 and 53). They lie enclosed in the upper free margin of the broad ligaments, and vary in length from 10 to 16 cm. (3 to 4 inches). They are not of equal length, the right being frequently longer than the left.

After leaving the superior angle of the uterus, the course of the tube is straight for about 2 centimetres (1 inch). It then curves outwards and forwards, and finally backwards and inwards, so that the whole tube has roughly the shape of a shepherd's crook (Fig. 22). Three parts come up for consideration-the isthmus, the ampulla, and the pavilion or fimbriated end.

The isthmus is the straight narrow part of the tube (fig. 22, 6), which at its internal end opens into the uterine cavity, and has a lumen barely admitting a bristle. On transverse section the diameter of the whole thickness is about 2 to 3 mm.

The ampulla is the curved and thick part of the tube (fig. 22, c), having an average diameter of about 6-8 mm., with a lumen admitting the ordinary uterine sound.

The free fimbriated end of the Fallopian tube (pavilion) is expanded and funnel-shaped; and it is provided with primary and secondary fimbriae surrounding the opening of the tube to which they converge. One special fimbria runs to the ovary (Fig. 22).

On section the Fallopian tube is seen to be made up of three layers from without inwards, viz., peritoneal, longitudinal and circular unstriped muscular fibres (the latter being inner), and mucous membrane lined with ciliated columnar epithelium. Connective tissue and elastic fibres lie between the peritoneal and muscular layers. No glands exist in the mucous membrane, which is much folded in a longitudinal direction especially in the ampulla.

It is remarkable that the ciliated epithelium lining the Fallopian tube and pavilion should be continuous with the squamous epithelium of the peritoneum; and that, further, there is direct continuity between the vagina, uterus, fallopian tubes and peritoneum, so that the peritoneal sac in the female is not closed as in the male.

Parovarium or Organ of Rosenmüller.-If the broad ligament be held between the light and the observer's eye, this rudimentary structure will be seen enclosed in its folds in the space between the ovary and ampulla (Fig. 22, d). It consists of closed tubules lined with ciliated epithelium, which converge towards the ovary and are united by a longitudinal tube [v. under Development]. Their pathological degeneration produces the cystic tumours known as parovarian.

OVARIES.

The ovaries, two in number, lie one on each side of the uterus, projecting markedly through the posterior layer of the broad ligament. Form, Size, and Relations.-The ovary is a small oval-shaped body about the size of a walnut, the weight of which varies from 60 to 135 grains. According to Farre its measurements are as follows:

The ovary has an anterior and posterior border, and an upper and lower surface. The posterior border is convex and free, the anterior flattened and attached to the broad ligament. It should be noted that this anterior border is called the hilus, and that the blood vessels and nerves enter there.

The position of the ovary will be discussed afterwards (p. 52), but at present it is sufficient to consider it as lying behind the broad ligament with its posterior border looking backwards and its outer end farther back than its uterine one.

Section of Cat's Ovary (Schrön). The free border of the ovary is, in the fig., above; the base of attachment-hilus-below. The division into Cortical and Medullary Layers is indicated. Note smallest Graafian Follicles at surface, and larger ones not so superficial. A Corpus Luteum lies to the left of the hilus. (f)

Ligaments of the Ovary. In addition to the attachment which the broad ligament gives to the ovary, two important ligaments are described the ovarian ligament and the infundibulo-pelvic ligament.

The Ovarian Ligament (fig. 22, f) is about 3 cm. (1 inch) long, and extends from the inner end of the ovary to the corresponding upper angle of the uterus, just below the uterine origin of the Fallopian tube. It is a longitudinal fold of the peritoneum into which the unstriped muscular fibre of the uterus is prolonged.

The Infundibulo-Pelvic ligament (fig. 22, i) is about 2 cm. long, and runs from the outer end of the Fallopian tube to the side wall of the pelvis. It is simply that part of the upper margin of the broad ligament unoccupied by Fallopian tube.

The Ovarian Fimbria (fig. 22, i) prevents the separation of the ovary and infundibulum tube. Thus the ovary is kept in position by its attachment to the broad ligament, by the ovarian and by the infundibulo-pelvic ligaments. Its own specific gravity has also a share, i.e., the ovary floats at a certain level.

Section through the Cortical part of the Ovary (Turner).

e Germ Epithelium; ss Ovarian Stroma: 1, 1 large-sized Ovarian Follicles; 2, 2 middle-sized; and 3, 3 smaller-sized Graafian Follicles; o Ovum within Graafian Follicles; v, v Bloodvessels in the Stroma; g Cells of Membrana Granulosa.

Structure of the Ovary.-The ovary is covered by epithelium differing from the squamous epithelium of the peritoneum in being made up of columnar cells with a dull lustre. It is continuous, however, with the peritoneal epithelium, the line of contact being marked by a whitish and elevated line. The epithelium covering the ovary is known as the germ-epithelium. This distinctive term is of importance in connection with the development of the ova and will be more particularly alluded to afterwards.

On section and microscopical examination, the ovary is found to consist of connective tissue with the structures known as the Graafian follicles embedded in it, along with blood vessels, nerves, lymphatics, and some unstriped muscular fibre. These are enclosed in the epithelial covering already described. The connective tissue is divided into a cortical and medullary layer; the former lying beneath the peritoneum, the latter being at and near the hilus (Fig. 23). The medullary layer is very vascular, and has some unstriped muscular fibre round the branches of the ovarian artery (Fig. 24).

The Graafian follicles are scattered through the whole substance of the ovary. The following points should be carefully noted.

a. The younger and smaller Graafian follicles lie in the cortical layer. Their size is generally about Tooth in., and they exist in immense numbers. According to careful estimates, the ovary of a female infant may contain 40,000 to 70,000 such follicles.

b. The larger follicles are much fewer in number and lie deeper in Size 3th to Tooth in.

the ovary.

c. There are also still larger follicles nearer the surface than the latter. These have advanced from the deeper layer (vide under Menstruation).

Structure of a Graafian Follicle.-This consists of

1. An envelope of connective tissue with capillary vessels;

2. The Membrana granulosa, a layer of nucleated columnar epithelial cells forming the discus proligerus at one part;

3. Fluid.

The ovum (size Too to To in. diameter) lies in the discus proligerus ;

it has

1. External envelope-zona pellucida,

2. Yelk protoplasm,

3. Germinal vesicle (both in. diameter),

4. Germinal spot ʊth in. diameter.

THE VAGINA.

The vagina is a mucous slit in the pelvic floor, extending from the hymen to the cervix uteri, and lying between the urethra and bladder in front and the rectum behind. In the upright posture it makes an angle of about 60° with the horizon, i.e., it is nearly parallel to the pelvic brim.

The vagina has two walls, an anterior and posterior, which are continuous at their sides. The anterior vaginal wall is triangular in shape, the base being above. Its lower limit is marked out by the hymen. At its upper end it is reflected down to a very small extent

on the anterior lip of the cervix uteri, the anterior fornix being thus formed (Fig. 25). It is closely incorporated with the urethra, but between it and the posterior aspect of the bladder there is loose connective tissue. Its length is about 5 cm., i.e., 2-2 inches.

a

く

Fig. 25.

Life-size drawing of Vagina in vertical section (Hart.)

a Perineum; b Urethra; c Vagina; e Anterior Lip of Cervix; f Os Uteri. The axis is not normal in its upper part, as the Uterus was drawn back. (†)

The mucous membrane of the wall is arranged in folds roughly transverse. At its lower end is a vertical mesial single or double thickening of the mucous membrane, about 2 cm. long, known as the anterior vaginal column (fig. 26, b). This begins near the urethral orifice or about 1 cm. above it. According to Budin, the columns are pro

longed on the hymen.

The posterior vaginal wall is triangular in shape and extends from the vaginal orifice upwards to the cervix uteri upon which it is reflected, thus forming the posterior fornix vaginae, which is deeper than the anterior one. Its length is about 7 cm. (3 inches), i.e., about 2 cm. (nearly 1 inch) longer than the anterior. It is also transversely rugous, and has a posterior column analogous to the anterior but smaller.

While the direction of the anterior vaginal wall is almost straight, that of the posterior vaginal wall is sigmoid (Fig. 27). The curve varies, however, according to the position of the uterus, and the fulness or emptiness of the adjacent bladder and rectum.

When the bladder and rectum are empty we find the direction of the vagina parallel to the pelvic brim. When the bladder is distended the