was known in the infancy of the world. When we seek to probe more intimately into the nature of menstruation we are still baffled, not merely as regards its cause, but even as regards its precise mechanism. "The primary cause of menstruation remains unexplained"; "the cause of menstruation remains as obscure as ever"; so conclude two of the most thorough and cautious investigators into this subject.[95] It is, however, widely accepted that the main cause of menstruation is a rhythmic contraction of the uterus—the result of a disappointed preparation for impregnation—a kind of miniature childbirth. This seems to be the most reasonable view of menstruation; i.e., as an abortion of a decidua. Burdach (according to Beard) was the first who described menstruation as an abortive parturition. "The hypothesis," Marshall and Jolly conclude, "that the entire pro-œstrous process is of the nature of a preparation for the lodgment of the ovum is in accordance with the facts."[96] Fortunately, since we are here primarily concerned with its psychological aspects, the precise biological cause and physiological nature of menstruation do not greatly concern us.
There is, however, one point which of late years has been definitely determined, and which should not be passed without mention: the relation of menstruation to ovulation. It was once supposed that the maturation of an ovule in the ovaries was the necessary accompaniment, and even cause, of menstruation. We now know that ovulation proceeds throughout the whole of life, even before birth, and during gestation,[97] and that removal of the ovaries by no means necessarily involves a cessation of menstruation. It has been shown that regular and even excessive menstruation may take place in the congenital absence of a trace of ovaries or Fallopian tubes.[98] On the other hand, a rudimentary state of the uterus, and a complete absence of menstruation, may exist with well-developed ovaries and normal ovulation.[99] We must regard the uterus as to some extent an independent organ, and menstruation as a process which arose, no doubt, with the object, teleologically speaking, of cooperating more effectively with ovulation, but has become largely independent.[100]
It is sometimes stated that menstruation may be entirely absent in perfect health. Few cases of this condition have, however, been recorded with the detail necessary to prove the assertion. One such case was investigated by Dr. H. W. Mitchell, and described in a paper read to the New York County Medical Society, February 22, 1892 (to be found in Medical Reprints, June, 1892). The subject was a young, unmarried woman, 24 years of age. She was born in Ireland, and, until her emigration, lived quietly at home with her parents. Being then twenty years of age, she left home and came to New York. Up to that time no signs of menstruation had appeared, and she had never heard that such a function existed. Soon after her arrival in New York, she obtained a situation as a waiting-maid, and it was noticed, after a time, that she was not unwell at each month. Friends filled her ears with wild stories about the dreadful effects likely to follow the absence of menstruation. This worried her greatly, and as a consequence she became pale and anæmic, with loss of flesh, appetite, and sleep, and a long train of imaginary nervous symptoms. She presented herself for treatment, and insisted upon a uterine examination. This revealed no pathological condition of her uterus. She was assured that she would not die, or become insane, nor a chronic invalid. In consequence she soon forgot that she differed in any way from other girls. A course of chalybeate tonics, generous diet, and proper care of her general health, soon restored her to her normal condition. After close observation for several years, she submitted to a thorough examination, although entirely free from any abnormal symptoms. The examination revealed the following physical condition: Weight, 105 pounds (her weight before leaving Ireland was 130); girth of chest, twenty-nine and a half inches; girth of abdomen, twenty-five inches; girth of pelvis, thirty-four and a half inches; girth of thigh, upper third, twenty inches; heart healthy, sounds and rhythm perfectly normal; pulse, 76; lungs healthy; respiratory murmur clear and distinct over every part; respiration, easy and twenty per minute; the mammæ are well developed, firm, and round; nipples, small, no areola; her skin is soft, smooth, and healthy; figure erect, plump, and symmetrical; her bowels are regular; kidneys, healthy. She has a good appetite, sleeps well, and in no particular shows any sign of ill health. The uterine examination reveals a short vagina, and a small, round cervix uteri, rather less in size than the average, and projecting very slightly into the vaginal canal. Depth of uterus from os to fundus, two and a quarter inches, is very nearly normal. No external sign of abnormal ovaries. She is a well-developed, healthy young woman, performing all her physiological functions naturally and regularly, except the single function of menstruation. No vicarious menstruation takes the place of the natural function, though she has been watched very closely during the past two years, nor the least periodical excitement. It is added that, though the clitoris is normal, the mons veneris is almost destitute of hair, and the labia rather undeveloped, while, "as far as is known," sexual instincts and desire are entirely absent. These latter facts, I may add, would seem to suggest that, in spite of the health of the subject, there is yet some concealed lack of development of the sexual system, of congenital character. In a case recorded by Plant (Centralblatt für Gynäkologie, No. 9, 1896, summarized in the British Medical Journal, April 4, 1896), in which the internal sexual organs were almost wholly undeveloped, and menstruation absent, the labia were similarly undeveloped, and the pubic hair scanty, while the axillary hair was wholly absent, though that of the head was long and strong.
We may now regard as purely academic the discussion formerly carried on as to whether menstruation is to be regarded as analogous to heat in female animals. For many centuries at least the resemblance has been sufficiently obvious. Raciborski and Pouchet, who first established the regular periodicity of ovulation in mammals, identified heat and menstruation.[101] During the past century there was, notwithstanding, an occasional tendency to deny any real connection. No satisfactory grounds for this denial have, however, been brought forward. Lawson Tait, indeed, and more recently Beard, have stated that menstruation cannot be the period of heat, because women have a disinclination to the approach of the male at that time.[102] But, as we shall see later, this statement is unfounded. An argument which might, indeed, be brought forward is the very remarkable fact that, while in animals the period of heat is the only period for sexual intercourse, among all human races, from the very lowest, the period of menstruation is the one period during which sexual intercourse is strictly prohibited, sometimes under severe penalties, even life itself. This, however, is a social, not a physiological, fact.
Ploss and Bartels call attention to the curious contrast, in this respect, between heat and menstruation. The same authors also mention that in the Middle Ages, however, preachers found it necessary to warn their hearers against the sin of intercourse during the menstrual period. It may be added that Aquinas and many other early theologians held, not only that such intercourse was a deadly sin, but that it engendered leprous and monstrous children. Some later theologians, however, like Sanchez, argued that the Mosaic enactments (such as Leviticus, Ch. XX, v. 18) no longer hold good. Modern theologians—in part influenced by the tolerant traditions of Liguori, and, in part, like Debreyne (Moechialogie, pp. 275 et seq.) informed by medical science—no longer prohibit intercourse during menstruation, or regard it as only a venial sin.
We have here a remarkable, but not an isolated, example of the tendency of the human mind in its development to rebel against the claims of primitive nature. The whole of religion is a similar remolding of nature, a repression of natural impulses, an effort to turn them into new channels. Prohibition of intercourse during menstruation is a fundamental element of savage ritual, an element which is universal merely because the conditions which caused it are universal, and because—as is now beginning to be generally recognized—the causes of human psychic evolution are everywhere the same. A strictly analogous phenomenon, in the sexual sphere itself, is the opposed attitude in barbarism and civilization