Menstruation, or the regular periodical discharge of blood from the uterus, is a phenomenon that occurs only in the human race and in some monkeys. The anatomical changes that accompany menstruation have not yet been definitely determined. In some species of monkey—Semnopithecus entellus and Macacus rhesus2—the following changes appear to take place at the menstrual periods: The endometrium first becomes swollen and congested as a result of the growth of the stroma, and increase in the number and size of the blood-vessels. The vessels in the superficial part of the stroma degenerate and break down, and blood is extravasated into the meshes of the stroma network. The extravasated blood collects into lacunÆ which lie close beneath the uterine epithelium. Finally the lacunÆ rupture and the blood escapes into the cavity of the uterus, forming the menstrual clot. Then a fresh epithelium grows over the torn surfaces, new blood-vessels are formed, the stroma shrinks, and the endometrium of the intermenstrual period is restored.

Nothing is known with any degree of certainty regarding the cause and significance of menstruation. There is much diversity of opinion in regard to the coincidence of ovulation and menstruation. Heape has shown that for monkeys ovulation and menstruation are not necessarily coincident; in forty-two menstruating specimens of S. entellus not one had a recently discharged follicle in either ovary. In monkeys, therefore, menstruation may take place without ovulation, and it is probable that the same is true for the human female. Ovulation and conception may occur in the human female when menstruation is absent; pregnancy not infrequently occurs during the amenorrhea associated with lactation, and in India, where the girls are married at a very young age, pregnancy and child-birth occur before menstruation has begun.

Leopold (quoted by Hirst) in an examination of twenty-nine pairs of ovaries removed on successive days up to the thirty-fifth after a menstrual period, found a Graafian follicle bursting on the eighth, twelfth, fifteenth, sixteenth, eighteenth, twentieth, and thirty-fifth days after the menstrual period. Thus ovulation frequently occurred without menstruation during the intermenstrual interval. In five cases there was no ovulation at the menstrual period, or menstruation occurred without ovulation.

It seems probable, therefore, that the ripening of the ovum in the ovary is independent of the process of menstruation, though the increased blood-supply to the generative organs during menstruation may, to a certain extent, determine the time of ovulation when a sufficiently ripe ovum is present.

Though menstruation in women is analogous to the rut or “heat” of other animals, yet there are some points of difference: The lower mammals breed only at times of “heat,” and these times of “heat” occur in the wild state only at certain periods of the year, which are dependent upon climatic conditions, the young being born at the season of the year best suited for their survival. Some domestic animals, like the cow, probably as a result of domestication, have no regular breeding time. In the lower mammals “heat” and ovulation appear to be coincident, and these are the only periods during which the female seems normally to have any sexual desire.

The monkeys examined by Heape menstruated throughout the year and yet seemed in the free state to have definite breeding times.

The human female, with but few exceptions, menstruates throughout the year and may breed at any time. The exceptions in the case of the human female are of interest. Dr. Frederick A. Cook,3 ethnologist to the first Peary North Greenland Expedition, says of the Esquimaux living in the extreme north, from the seventy-sixth to the seventy-ninth parallels of latitude: “The passions of these people are periodical, and their courtship is usually carried on soon after the return of the sun; in fact, at this time they almost tremble from the intensity of their passions, and for several weeks most of their time is taken up in gratifying them. Naturally enough, then, the children are usually born at the beginning of the Arctic night.” In Queensland the natives are also said to have a special breeding season.

Menstruation usually begins in this country at the fourteenth year. The time of the first appearance of the process is influenced by race, climate, and environment. As a rule, it begins earlier in warm climates and later in cold climates. It is earlier in girls who lead luxurious, indolent lives than in girls of the working classes.

During the first year or two of menstrual life menstruation is often very irregular. It may be absent for several months after its first appearance, or recur at varying intervals before it becomes regularly established. Irregularity at this time calls for no treatment.

Precocious menstruation rarely occurs at a very early age. It has been known to begin, and to recur with regularity, from the time of birth. In such cases there is a corresponding premature development of the sexual organs.

The menstrual discharge consists of blood, mucous secretion from the uterus and vagina, and epithelial cells from the endometrium.

The normal duration of the flow is from two days to a week. The amount of fluid discharged is from 2 to 9 ounces. Menstruation occurs every twenty-eight days, counting from the beginning of one period to the beginning of another. The menstrual interval is subject to considerable individual variations, which appear to be within the limits of health. It sometimes occurs with regularity every two, three, or five weeks. When it occurs every two weeks, the alternate flows are often but small in amount. The occurrence of, or the attempt at, menstruation every two weeks, in a woman who had previously menstruated monthly, is sometimes a symptom of beginning uterine disease.

Menstruation commonly ceases at about the forty-fifth year, when the menopause appears.

Most of the disorders of menstruation have already been considered as symptoms of the various lesions of the genital organs that have been described in the previous pages.

There are some disorders of menstruation, however, often unaccompanied by discoverable lesions, which now demand consideration.

Amenorrhea.—Amenorrhea is the absence of menstruation. Failure of the menstrual blood to be discharged from the vagina, such as occurs in cases of atresia, is not necessarily amenorrhea; menstruation may have taken place, though the most marked phenomenon of this process, the discharge of blood, is concealed.

The term primary amenorrhea, or emansio mensium, is applied to those cases in which menstruation has never appeared. Secondary amenorrhea, or suppressio mensium, is applied to those cases in which menstruation has ceased after having once been established.

Amenorrhea is due to defective development of the organs of generation; to premature atrophy, such as occurs in superinvolution of the uterus; to lesions, pathological and traumatic; to acute and chronic general diseases; and to psychical disturbances.

Menstruation is often absent during the acute diseases, such as typhoid fever, and it may remain suppressed until the general health is fully restored.

Amenorrhea may also occur in any chronic debilitating condition. It is common in chlorosis, anemia, phthisis, and malaria.

It frequently results from changes of climate and surroundings, and continues until the person becomes adapted to the new environment. It is seen in emigrants from other countries, and in women who move from the country to large cities. It is often caused by overwork, physical and mental, and by insufficient food. It is not uncommon in studious school-girls.

Amenorrhea is sometimes due to the excessive general development of fat, even in young woman who are apparently in good general health.

Amenorrhea is frequently associated with insanity. It may be caused by fright, grief, or anxiety. The fear of pregnancy after illicit coitus sometimes produces it.

In some unusual cases amenorrhea is present without any discoverable cause. The woman may be in perfect general health, and the sexual organs may be well developed, at least so far as can be determined by physical examination.

In amenorrhea there is often a general periodical disturbance that marks the times at which the menstrual bleeding should occur. There may be headache, flashes of heat, nervousness, nausea and vomiting, and a feeling of fulness and pain in the pelvis. Various cutaneous eruptions may occur as the result of amenorrhea, as in other diseases of the genital apparatus.

The poor health, mental and physical, that usually accompanies amenorrhea is often thought by the patient and her friends to be the result, rather than the cause—as it really is—of the arrested bleeding.

Treatment.—The treatment of amenorrhea depends upon the cause of the condition. Little, if any, benefit is to be expected in those cases due to defective development of the uterus or the ovaries. If an attempt at menstruation is made, as shown by periodical local pain and general disturbance, and the uterus is found to be small and sharply anteflexed, benefit may sometimes result from thorough dilatation of the cervix.

Most cases of amenorrhea demand general treatment. The mode of life should be regulated according to strict hygienic principles. Fresh air, sunshine, baths, and suitable exercise should be prescribed. Studious girls should be made to lead more active lives. A change of surroundings is beneficial. A visit to the seashore and salt-water baths are of advantage.

The general health should be improved by the administration of iron, strychnine, or some other tonic. Blaud’s pill and the hypophosphites are useful. Obesity should be relieved by a regulated diet and exercise. The regularity of the bowels should always be carefully attended to. Most of the so-called emmenagogues are of but little, if any, value. Benefit is sometimes derived from the use of potassium permanganate (gr. j-ij three times a day) and the binoxide of manganese (gr. j-ij three times a day). These medicines should be administered in pill form for several weeks.

Oxalic acid in doses of from ? to ¼ of a grain, given in lemon syrup for a period of from one to four months, has been recommended, and is sometimes very useful.

It seems probable that pelvic massage practised for a period of several months may result in benefit.

Acute suppression of menstruation during a menstrual period is a phenomenon to which the term amenorrhea is not properly applicable. It may be caused by exposure to cold or by some sudden emotional disturbance during the menstrual flow.

The condition may be unaccompanied by any subjective symptoms, or there may be present ovarian and pelvic pain.

The treatment consists in rest in bed, the application of warm fomentations to the lower abdomen, and hot foot-baths. Especial care of the general health should be observed at the following menstrual period.

Scanty Menstruation.—Scanty menstruation occurs when the menstrual flow is much less than normal. It must be remembered that individual peculiarities in this respect may be within the limits of health. When one or more periods are missed, and the flow shows a continual tendency to diminish in amount, treatment may be demanded.

The causes and the treatment of scanty menstruation are those which have already been considered under Amenorrhea.

Vicarious Menstruation.—Vicarious menstruation is the discharge of blood, at the menstrual periods, from some part of the body other than the uterus. In some cases, instead of a discharge of blood, a secretion of another character takes place.

The vicarious discharge may be the only phenomenon present, or it may occur supplementary to the normal uterine bleeding.

The vicarious bleeding may take place from almost any part of the mucous or cutaneous structures. It occurs from the nose, the throat, the lungs, the stomach, the bladder, and the anus. It may occur from an ulcer or other lesion of the external surface. Sometimes the cutaneous hemorrhages appear in the form of ecchymoses.

Various secretions may take the place of the bleeding. A monthly flow of milk from the breasts has been observed, and a periodical diarrhea or leucorrhea has taken place.

Vicarious menstruation is a rare condition. It may occur in defective development of the uterus and ovaries. It is usually found in debilitated nervous women, and accompanies a deficient menstrual discharge from the uterus.

Treatment.—Direct local treatment should be applied to the vicarious bleeding only when it becomes excessive. The general health of the woman should receive attention. Treatment should be applied to any local lesion of the genital apparatus that may be discovered. The directions given for amenorrhea are also applicable here.