Fig. [86].—Diagrammatic representation of the Graafian Follicle.
Fig. [87].—Ovary of a girl aged 19 years. (Normal size.)
Fig. [88].—Ovary of a woman 72 years of age. (Normal size.)
In the last stage of this retrogressive metamorphosis, we find the follicle completely transformed to a fibrous mass. It appears as an elongated oval body, much lobulated, connected with the surrounding stroma by thick strands of fibres; a trace of the original cavity can still be distinguished in the form of a narrow cleft, without distinguishable contents. The tissue of this body consists of connective tissue fibres, with interspersed nuclei and nuclear fibres (Fig. [91]).
The three stages I have observed in the retrogression of the follicle, of which I have given a summary account above, may, I think, be explained in the following manner: When the woman’s reproductive activity ceases, the graafian follicles become subject to a retrogressive metamorphosis, a fatty degeneration setting in in the cells of the membrana granulosa and in the ovum, until ultimately the whole of the granular epithelium has undergone atrophy. The follicle now undergoes a vesicular transformation with shrinkage of its cavity, and with the formation of a new tissue which appears to be young connective tissue. As time goes on, this new connective tissue is formed in increasing quantities, until finally the entire follicle is transformed into a firm fibrous mass.
Fig. [89].
Thus we are led to infer that the gradual but extensive thickening of the tunica albuginea (i. e., the outer, condensed layer of the ovarian stroma), which, as we have seen, always occurs at the climacteric period, offers a hindrance to the bursting of the follicles as they mature, and in this we find the explanation of the irregularity of menstruation and of the various troubles which attend the performance of that function at the time of the menopause. It is reasonable to assume that the resistance of this thickened tunica albuginea is responsible for the fact that the interval between the bursting of the successive follicles is now greater than normal, as much as six or eight weeks—this retardation of menstruation being one of the commonest ways in which the onset of the menopause is first manifested. Another phenomenon connected with the onset of the menopause also finds a plausible explanation in the anatomical grounds just mentioned. As already pointed out, in parous women the menopause sets in later than in nulliparae. At every pregnancy, the ovaries share in the more abundant nutrition of all the reproductive organs, due to the general dilatation of the intrapelvic vessels which accompanies this process; hence the ovaries become larger, richer in lymph, and therefore softer, the cellular elements increase in size, and perhaps also in number, and it is readily conceivable that in such ovaries the cellular elements are able for a longer time to resist the induration and the new formation of connective tissue which occur at the climacteric.