FUNCTIONS OF THE OVARY.
surrounded by the layer of granules which constitutes the lunica granulosa, and externally to this the radiating bands or retinacukt, the whole of those parts, external to the ovum, being composed of nucleated cells.
Besides these structures, the Graafian follicle contains a pellucid albuminous fluid, of a slightly yellowish colour, partially coagulable by heat. In this fluid float numerous granules similar to those of which the parts just de scribed are formed, together with a varying quantity of oil-like globules.
Lastly, in the midst of the granules at an early period, and subsequently in that more de finite arrangement of them which constitutes the hollers granulosa, is contained the ovum (fig. 374. f, and A. 376.), a full description of which is given in the article under that title.
4. Vessels and ovary de rives its supply of blood chiefly from the ovarian (spermatic), but in part also from the uterine arteries. So free, indeed, is the com munication between these vessels, that the organ may be equally well injected from either source. The communication is effected chiefly by means of a branch of the ovarian artery, which passes inwards to inosculate with a ter minal branch of the uterine artery, this anas tomotic branch being occasionally so large as to constitute the principal source of supply of the ovary. The terminal vessels are con The ovary is to the female what the testis is to the rnale—the germ-preparing organ, the part in which is formed the female generative element, and therefore the essential portion of the entire sexual apparatus. To it all other structures may be regarded as accessory or superatIded ; for in by far the largest proportion of the animal kingdom they are either found in a rudimentary state, or else have no existence. But not only is the ovary the organ in which the formation and evolution of the germ take place ; its offices farther extend to the separa tion and expulsion of the ova, when they have reached such a state of maturity as will render them susceptible of impregnation. This process, commonly termed ovulation, takes place spontaneously, and without the intervention of the male, which is not neces sary thereto. All animals possessing an ovary
are subject to this law ; and Man constitutes no .exception to the rule. But the functions of the ovary are exercised only during a cer tain period of life. The ova, which are formed at or near the time of birth, and sometimes before that event, are not called into activity until the body. of the parent is sufficiently developed, to suffer the parturient act without destruction or serious detriment to its own tissues, such as would be incompatible with the continuance of its own life, and such as is witnessed in those lower tribes where the whole of the vital energies of the parent are exhausted by one effort of reproduction, or its tissues are even disrupted by the process which produces its kind. But long before the time arrives at which the generative faculty is capable of being fully exercised, it is probable that many of the ova which were first formed have perished, their place being continually supplied by new formations.1- Their numbers, however, are so great that, if only the one thousandth part of those originally contained in the ovary remain, and no new ones are superadded, there will still be more than sufficient for all the purposes of reproduction. But as the functional activity of the ovary, so far as relates to the emission of ova in a state fit for impregnation, is restrained on the one side until the arrival of a certain stag,e of development of the parent, so on the other a period equally arrives, after which this power of producing and emitting ova altogether fails; and it is plain that both these restrictions con tribute to one and the same end, the limita tion, namely, of the office of reproduction to that period of life in which the vital energies of the producing body, having attained to full perfection, remain still unimpaired, so that the qualities of health and vigour in the parent may be transmitted undiminished to the off: spring.