5. The ripe follicle which is about to rup ture and discharge an ovum. It is always found at the surface of the ovary, projecting often to a distance of 3-4"'. It is covered by numerous veins, and in the centre of the most prominent part the coats of the follicle, as well as the ovarian coverings, are thinned and partly absorbed. Their thinness permits the contents of the follicle to be partly visible, and thus is produced a brownish red colour at this spot. The follicle contains blood or a bloody fluid, and sometimes a clot. The cavity is of considerable size, 4-6m. The inner coat is of a bright yellow colour, and ex hibits slightly wavy folds (figs. 380. and 381.).
6. The follicle which has already ruptured. An irregular lacerated opening extending 1-2"' is perceptible in the centre of the attenuated part, through which the ovum, together with that portion of the membrana granulosa which lay beneath the seat of the rupture, has es caped, or is about to escape. The follicle is beginning to collapse. Its walls, no longer distended, become folded into numerous small plaits, producing, on section, the ap pearance resembling cerebral convolutions. The cavity is consequently diminished. It is empty, or contains a little bloody fluid or a clot (fig. 385.).
Descending Series. A. Not pregnant.
7. In the follicle which has recently burst, shrinking has commenced. The yellow ovisac is much plicated. The cavity contains a clot which is becoming pale,and exhibits under the microscope distinct fibrillation, or the cavity is empty and much contracted.
8. The shrinking having rapidly progressed, the ovisac exhibits deep plications, and the rays are beginning to form, but the yellow colour is still distinct.
9. The cavity is nearly or entliely oblite rated. The yellow colour is gone, but the rays remain, and the collapsed follicle now forms a white stellate body with a small cen tral point (fig. 372. h ).
10. The follicle itself is reduced to a mere point in which none of the foregoing characters can be traced.
Descending Series. B. After Impregnation.
11. The follicle has not materially dimi nished in size. The lacerated opening is closed. The yellow coat is much plicated, and the clot when present shows fibrillation, as in No. 7., or the cavity is empty.
12. The follicle has acquired greater firm ness and solidity. The yellow ovisac is much increased in thickness. The folds are not so numerous, but are deeper, though not quite so distinct. Vessels contained between the folds appear to pervade the yellow coat. The white lining of the cavity is formed, and within it is a clear fluid, rather viscid, ( fig. 387.), or the centre of the yellow ovisac is solid, and exhibits no cavity.
13. The central cavity is nearly or entirely obliterated. In the latter case a solid white body occupies its place, extending into the yellow mass in divergent rays. This arises from the plication of the white lining, by which process the cavity is closed. The co lour of the principal mass is now a dirty yellow ; it is somewhat reduced in size, and its outline is oval or irregular (fig. 389.).
14. The more prominent features observable in the last condition may still be faintly traced.
In size the body measures 2-3"'. It is of a pale white, and is chiefly distinguishable from the surrounding stroma by the absence of vascularity in its tissues. Its solidity is gone.
To return, then, to the two questions which led to the foregoing considerations as neces sary to their solution, viz.— 1Vhat evidence does the condition of the ova rian follicle afford, first, as to the previous es cape of an ovum, and secondly, as to the pro bability or certainty that that ovum has been impregnated or otherwise It may be concluded that whenever the follicle presents the appearances exhibited in the first series down to and including No. 5., the ovum has not escaped ; although it may not be detected, either on account of the difficulty of finding so small a body, or else because it may have perished by. absorption or decomposition.
In the condition No. 6., an ovum has just escaped, or is in the act of escaping. None of these conditions of the follicle afford the slightest evidence of previous impregnation. They have all been repeatedly observed both in Man and animals where the coitus has never occurred.
Between No. 7. and No. 11. it may be diffi cult to draw a positive distinction. No con clusion regarding the question of previous fecundation, derived from the state of the fol licle during the first fortnight after the escape of an ovum, would be absolutely safe ; al though the difference between the unimpreg Dated and the impregnated is such as to afford in every instance at least strong presumptive evidence, for the follicle shrinks rapidly in the former, while in the latter it undergoes little or no diminution in size.
But after this period there can be no ques tion as to the prior occurrence of a fecun dating coitus. Every follicle presenting the conditions described in Nos. 12, 13, and 14 has discharged an ovum, which has been after wards impregnated. Every follicle in the states described in 8, 9, and 10 has discharged or has contained an ovum which has perished. But this proves only that fecundation has not occurred. It affords no evidence whatever that the coitus has not obtained.
Lastly, it may be observed that if, as is sometimes the case, the follicle fails to com plete the process of rupture after the first steps of preparation have been made, the ovum may perish or be absorbed without being dis charged, and the follicle will then shrink and become obliterated, as in the first series of changes. And it is further noticeable that although the number of Graafian follicles ex hibiting the appearances indicative of the dis charge or fecundation of ova, may generally be taken to represent the number of ova also actually discharged or fecundated, yet this will not always furnish a safe guide, because one follicle may contain two ova, or one or more ova may have escaped the influence of the coitus which had fecundated the rest. The number of ruptured or altered follicles there fore will in the first case be less, and in the second greater, than the number of ova or fcetuses found in the oviducts or uterus.