Page:Proceedings of the Royal Society of London Vol 60.djvu/224

204 Stage VI.—The uterine epithelium degenerates and ruptures, and the blood contained in the lacunse is poured into the uterine cavity.

Stage VII.—Denudation follows, and the formation of the mucosa menstrualis takes place in the same way and to the same extent as in S. entellus.

Stage VIII.—The recuperation takes place as in S. entellus. With regard to the new uterine epithelium I find fresh evidence in support of my contention that it is formed, not solely from epithelial elements which already exist, such as the torn edges of glands, but also directly from elements of the stroma tissue.

Ovulation inMacacus rhesus.—Only one case has been met with in which it can possibly be supposed that ovulation and menstruation have occurred. simultaneously; this is the only case in which a recently discharged follicle was found in the ovary of a menstruating Macacus rhesus; it does not follow that ovulation in this case was brought about by menstruation ; indeed, the absence of any sign of the recent bursting of a follicle in any other of the seventeen cases examined is in itself strong presumptive evidence that the two processes are distinct.

This result may be confidently asserted for Macacus rhesus during the non-breeding season; at the same time it must be remembered that I have not investigated Macacus rhesus during the pairing season; probably at that time ovulation may be more frequent, and may more often be coincident with menstruation; but, however that may be, menstruation occurs in Macacus rhesus regularly without ovulation taking place, and my former views are confirmed, namely, that ovulation does not necessarily occur during each menstrual period, and that it is not necessarily brought about by menstruation.

I feel warranted in going further than this and asserting that the regular occurrence of menstruation without ovulation, even though it be in the non-breeding season, is sufficient evidence that ovulation is a distinct process, and that it depends upon a law or laws other than the laws which govern menstruation.

The Discharged Follicle.—The changes undergone by the discharged follicles of Macacus rhesus during the non-breeding season are of interest. Very shortly after rupture the follicle is pear-shaped, and the place where rupture took place is to be seen in sections.

The wall of the follicle is composed of branched cells which, along the inner edge of the follicle, are longitudinally disposed and form a denser layer sharply defining the wall from the central cavity.

The cavity contains a network of densely granular material and no blood clot.