Until lately, the ovary has been considered to be composed of an ex ternal serous envelope, of a fibrous envelope proper, a tunics albuginea, and of a spongy substance in which the ovules were developed.
Nearly at the same time SchrOn (1862), and Sappey (1863), demon strated that hitherto authors had been deceived, and that, 1st, the serous or peritoneal envelope only exists as an epithelial layer; 2d, that the fibrous envelope does not exist; 3d, that the spongy part contains neither ovules nor Graafian follicles.
When the ovary is cut perpendicularly to its surface, and completely through, we see that it is composed of two parts: 1st, A superficial part, white, firm, and of a homogeneous appearance. 2d, A central reddish part of a spongy consistency.
The superficial portion is the exclusive seat of the ovary-vesicles; the deep, or central, part consists of bundles of muscular and laminated fibres. The former is the glandular, or ovigenetic layer; the latter the vascular, or bulbous portion.
The bulbous portion forms the body of the gland. It supports. the glandular, or ovigenetic part. It is more or les:; of a reddish color, de pending upon the state of congestion of the bulb, and consists of muecu• lar fibres, of fibres of connective tissue, and of vessels and nerves.
The muscular fibres, first described by Rouget in 1858, proceed from the ligament of the ovary, from the ligament of the tube, from the pos terior round ligament, and from the posterior fold of the broad liga ment. They pass from below upward, at the same time spreading out, and crossing each other.
The fibres of the connective tissue follow the entire course of the vessels. Mingled with them are a great number of fusiform fibro-plastic bodies.
The arteries spring from the utero-ovarian artery. All enter the bulb through the hilum, and are eminently flexuous and helical. They anas tomose, and form a net-work, the meshes of which grow smaller as they approach the surface of the gland.
The veins are very numerous and very large. By their anastomosis they form a plexus, from which arise the capillaries. These become trunks, and empty into the utero-ovarian vein.
The very numerous lymphatics form eight or ten trunks, which pass from the hilum of the gland to the lumbar glands.
The nerves proceed from the ovarian plexus.
Rouget considered the bulb an erectile organ; but according to Sappey it can not be a trae erectile organ, having only the appearances, without the real formation.
II. The Oviyenetic Layer.
This is the peripheral portion, the essential part of the ovary. It is 0.39 of an inch thick, and is smooth, even in young girls and young women. When the ovary is covered with cicatrices it becomes uneven. It is composed of an epithelial layer, of a fibrous layer, of fusiform fibro plastic bodies, of vessels and nerves, and finally of ovarian vesicles, and the follicles of De Graaf. (See Figs. 58, 59, 60.) 1st. Epilhelium.—It is formed by a single layer of ovoid, or rather prismatic cells, and covers the whole surface of the ovary, except at the hilum.
2d. Fibrous Layer.—This serves as a frame-work of support. It is composed of laminated fibres, studded with numerous fusiform fibro plastic bodies (Robin). It adheres to the epithelium by its external sur face, and is continuous with the laminated fibres of the bulb; there being no distinct line of demarcation. It is of a white color.
3d. Vessels and _Verves.—The blood-vessels are very numerous, and form, by their anastomoses, a thick net-work. The final arterial twigs spread over the circumference of the ovarian vesicles. The veins are
continuous with those of the bulb. The nerves follow the course of the arteries.
III. Ovarian Vesicles.
These are the envelopes of the eggs, or ovules, the ovisacs of Barry De Graaf, in 1672, was the first to carefully describe them, hence the name vesicles of De Graaf or Graafian follicles.
The Graafian follicles are all in the peripheral portion, and in a child of two years there are about 400,000, and still more in the foetus. They increase, at the age of from 18 to 20 years, to about 350,000 per ovary, or nearly 700,000 for each woman. A woman therefore has, when in the ftptal condition, all the vesicles that she is to have later. They are not absolutely found only in the peripheral portion of the ovary, and if, after puberty, some seem to be found in the bulbous portion, this is caused by the development of some of them, which then extend beyond the ovigcnetic layer, and penetrate the bulbous layer, becoming larger the deeper they go. (Fig. 30.) From the moment of birth to puberty, the ovisacs and ovules scarcely change. They are spherical, having a diameter not exceeding of an inch. Their walls consist of connective tissue, which is thin yet resist ing. They do not contain fluid, but are filled with epithelial cells, and with the ovule. At the moment of puberty, a number of these vesicles develop, acquire the volume of a millet seed, a piece of shot, or even a pea. One comes to complete maturity in from three weeks to a month, and bursts and allows the ovule to escape. This phenomenon is repro duced at each menstrual epoch; we will study it in detail further on. The ovisac, at this epoch of complete development, is composed of: 1st. A wall, or enveloping capsule, which has the appearances of reticu lated tissue, and which becomes highly vascular. According to Robin, it is composed of laminated fibres piled one against the other, of a trans parent amorphous material in fine granulations, and of voluminous poly hedral cells with rounded angles, which are found only in the wall of the ovisac, and in the uterine mucosa developed during pregnancy.
2d. A clear viscid liquid.
3d. A layer of small round cells with nuclei, which are next to the internal face of the enveloping capsule. This is the granular membrane (membrana granulosa). These cells are denser and more numerous at one point, and form by their union at this point the discus or cumulus proligerous. At the centre of this disc the ovule is found.
IV. The Ovule.
The ovule (Fig. 31) was discovered by de Baer in 1827. It is spherical in shape, and it is composed of three parts: 1st. An envelope or vitelline membrane. This is thick, elastic, resist ing, transparent, of a homogeneous aspect, and an amorphous nature.
2d. A granular liquid, the vitellus. This is analogous to the yolk.
3d. A transparent vesicle, the germinal vesicle, the vesicle of Purkinje, who discovered it in birds. It was only discovered in 1834, in mam malians by Coste. It is spherical, extremely tenuous and transparent. It is formed by al amorphous membrane which encloses a liquid limpid as crystal. It is about Tb of an inch in diameter.
In this vesicle, Magner observed a peculiar corpuscle which he called the germinal spot.
V. Embryogenetic Vesicle.
In certain species of animals Balbiani has observed and described in the ovule a particular body, or special vesicle, which he called the embryo genetic vesicle. This is destined to form the plastic matter which aids the development of the new being. (Tarnidr.)