Napier believes that the ovaries secrete specialized substances which aid in determining menstruation; and that in a less degree the utricular glands and the glands of the Fallopian tubes share in this action.  He considers that this is probably secondary to the chain of peripheral irritation from the uterine glands, but that this secretion is none the less an essential feature of the menstrual process.

In support of this view he calls attention to the pigmentation of the skin which occurs during pregnancy and chlorosis, showing that the absence of the catamenia results in the retention in the blood of some substance which would normally be excreted at this time.

Other atrophic changes in the genitalia are shriveling of the vulva, with prolapse of the vagina or uterus from relaxation of the ligaments and loss of the natural support afforded by the changed perineal body.

Uterine catarrh occurs almost invariably, and only ceases in advanced years.  Displacements of all kinds are frequent, but on account of the now greatly diminished weight of the uterus, these are insignificant.

The vagina is at first almost always hyperemic, but this disappears as the vessels successively atrophy.  The vagina gradually becomes narrower and shorter.  The mucous membrane loses its rugae and presents a pale, grayish, blanched hue.

The researches of Byron Robinson, made by the dissection of a number of old women, show that after the menopause not only is there an atrophy of the genital organs, but that the hypogastric plexus of the great sympathetic nervous system also shrinks away.  “It becomes smaller and firmer, and no doubt some strands disappear.  On this fact must he based the pathologic symptoms accompanying the cessation of the menstrual function.”

The importance of the genital organs is shown by the vast nerve-supply sent to them.  When this great nerve-tract becomes atrophic, so that it can no longer transmit the higher physiologic orders, all parts of the sympathetic system must be unbalanced, until a new line, the next line of least resistance is established.  And Robinson believes that this is the explanation of the many pathologic manifestations of every viscus at the menopause; that is, “the irritation which arises by trying to pass more nervous impulses over plexuses than normal gives origin to what is unfortunately known as functional disease.  It is just as organic as any disease, only we are unable to detect it.”

Chemical changes in the blood and tissues are constant vital phenomena; increased oxidation causes increased activity of the circulation, increase of temperature, increase of urea and carbonic acid in the economy from retrograde changes, and, finally, during menstrual life the flow of blood from the uterus carried off the effete materials from the highly charged system.

The elimination of albuminoids, as shown by the altered condition of the blood after menstruation, is greater than can be accounted for by the blood discharged.  When the menopause is attained suddenly, the retention of such albuminoid substances must act toxically.  Hence the resulting clinical fact that sudden cessation of the menses is, in the majority of cases, attended with pronounced symptoms of discomfort, and it is in these cases that untoward results are most likely.