The same regular sequence of changes, which may always be traced in the Mammalia, though with some slight variations according to species, occurs also in man. If the exami nation be made in a young and previously healthy woman, who has menstruated regularly up to the time of her death, there will gene rally be found in the ovary one or more fol licles in conditions sirnilar to those just de scribed. The ordinary state in which the Graafian follicle is found has been explained at p. 550. Vesicles in the state there de scribed may be seen at all times in the healthy ovary, sometimes near its surface, and at others buried more deeply ; but when they increase in growth beyond this size, and are preparing to rupture, one or more will always be found approaching the periphery of the ovary, or rising above the level of its outer tunics, constituting there a nipple-like pro minence, so distinct as at once to arrest attention, and to point out the part of the ovary in which the dehiscence will next occur (fig. 380. a).
peculiar brick-red colour. Around the mar gin or base of the prominence the fibres of the tunica albug,inea are often seen to be separated at short distances, forming concentric lines or interrupted circles ; the red contents showing through the interspaces, and producing an appearance of alternate white and red lines (fig. 380. b). Beyond this circumference, the base of the promi nence exhibits the usual white colour of the ovarian coverings. Numerous red vessels, chiefly veins (fig. 380. c), ramify towards the projecting spot, and some of these traverse it to its summit, coursing over the promi nence in serpentine lines, and forming here a rich plexus.
A clean section through the centre of the projecting follicle lay's open an ovoid cavity, In general, only one follicle will be found preparing for rupture ; but sometimes two, or possibly three, may be observed in the same condition in one ovary. The growth has now been so considerable, that instead of measuring only 11-m-21'", or even 3'", it has now a di ameter of 5.1-7"', the breadth being usually somewhat lesa than the length, for it rarely happens that the follicle is perfectly' spherical. In consequence of this increased growth the follicle projects from the surface, and causes the swelling just described, whilst the accu inulation of fluid within it produces a softness and sense of fluctuation in this part of the ovary, which is very obvious to the touch. Over the centre of this projection the pe ritoneum is exceedingly thin, and in some places is wanting, partly from absorption, and partly from laceration, the result of over stretching and distension.
The tunica albug,inea also of the ovary may be absorbed, or may have become so exceedingly thin, as to permit the blood coloured contents of the vesicle partially to appear through it, giving to the spot a (fig. 381. a), containing usually a deep red clot, b, together with a certain quantity of blood and a bloody fluid. The clot has as
yet no adhesion to the walls of the cavity, and is easily washed away.
If the ovary has been examined not too long after death, the ovum may possibly be found lying imbedded in the granules of the mon brain; granulosa, immediately beneath the most projecting point of the follicle. But more commonly, the examination not being rnade until after this delicate membrane has melted down, and its granules have become dispersed by post-mortem change, the ovum cannot be discovered.
After washing out the contents of the follicle, the inner surface of the ovisac is ex posed (fig. 381. c). This I have occasionally seen to be of an intense red colour, from the surface being covered by a rich network of ca pillaries filled with blood. But most com monly the colour of the ovisac throwthout as . .
far as the outer tissue of the follicle, is at this time a clear, pale, chrome yellow, this coat being now also very' soft in texture. It is important to observe that the yellow colour includes the whole thickness of the ovisac, or inner coat of the Graafian follicle, which now mea sures from to 1"' in thickness, but that it extends no further ; the outer coat, or theca folliculi, retaining its ordinary condition. Already a slightly wavy outline is perceptible in the follicle (fig. 381.), which is due to the growth of the inner membrane having con tinued after the outer coat has ceased to ex pand.
The inner coat of the follicle, when it has thus acquired a yellow colour, is seen, by the aid of the microscope, to have undergone an important and yet very simple change. On its inner surface, or that which is turned towards the cavity of the ovisac, it presents the appearance of a transparent and nearly structureless membrane, in the substance of which are imbedded numerous oil droplets, very minute, and aggregated in little masses, with a certain regularity which suggests the idea that they have either been originally deposited around a centre globule, or are contained in cells or vesicles, the cell-wall of which is not very discernible (fig. 382. b). Deeper towards the outer surface of the ovisac the oil droplets or granules become so numerous as to prevent the recognition of any other structure until the greater portion of the oil has been dissolved out by macerating the part in ether. If, after this process, the tissue which remains be washed in spirit or water, and subsequently treated by acetic acid, it is seen to be composed of numerous blood vessels, and of developed as well as embryonic fibres of connective tissue, which latter, how ever, are only faintly indicated, and are con nected together by a transparent membrane. The proportion of developed fibres of con nective tissue is here very large, whilst in less advanced follicles the embryonic fibres preponderate (fig. 375.).