amount. Various explanations of this fact have been given. It was formerly supposed either to contain no fibrin, or an unusually small amount. Retzius attributes its non-coagulation to the presence of free lactic and phosphoric acids. The true explanation was first given by Mandl, who proved that even small quantities of pus or mucus in blood were sufficient to keep the fibrin in solution; and mucus is always present to greater or less amount in the secretions of the cervix and vagina, which mix with the menstrual blood in its passage through the genital tract. If the amount of blood be excessive, however, the mucus present is insufficient in quantity to produce this effect, and coagula are then formed.

On microscopic examination the menstrual fluid exhibits blood corpuscles, mucous corpuscles, and a considerable amount of epithelial scales, the last being the débris of the epithelium lining the uterine cavity. According to Virchow, the form of the epithelium often proves that it comes from the interior of the utricular glands. The color of the blood is at first dark, and as the period progresses it generally becomes lighter in tint. In women who are in bad health it is often very pale. These differences doubtless depend upon the amount of mucus mingled with it. The menstrual blood has always a characteristic faint and heavy odor, which is analogous to that which is so distinct in the lower animals during the rut. Raciborski mentions a lady who was so sensitive to this odor that she could always tell to a certainty when any woman was menstruating. It is attributed either to decomposing mucus mixed with the blood, which, when partially absorbed, may cause the peculiar odor of the breath often perceptible in menstruating women; or to the mixture with the fluid of the sebaceous secretion from the glands of the vulva. It probably gave rise to the old and prevalent prejudices as to the deleterious properties of menstrual blood, which, it is needless to say, are altogether without foundation.

It is now universally admitted that the source of the menstrual blood is the mucous membrane lining the interior of the uterus, for the blood may be seen oozing through the os uteri by means of the speculum, and in cases of prolapsus uteri; while in cases of inverted uterus it may be actually observed escaping from the exposed mucous membrane, and collecting in minute drops upon its surface. During the menstrual nisus the whole mucous lining becomes congested to such an extent that, in examining the bodies of women who have died during menstruation, it is found to be thicker, larger, and thrown into folds, so as to completely fill the uterine cavity. The capillary circulation at this time becomes very marked, and the mucous membrane assumes a deep-red hue, the network of capillaries surrounding the orifices of the utricular glands being especially distinct. These facts have an unquestionable connection with the production of the discharge, but there is much difference of opinion as to the precise mode in which the blood escapes from the vessels. Coste believed that the blood transudes through the coats of the capillaries without any laceration of their structure. Farre inclines to the hypothesis that the uterine capillaries terminate by open mouths, the escape of blood

1

2

through these, between the menstrual periods, being prevented by muscular contraction of the uterine walls. Pouchet believed that during each menstrual epoch the entire mucous membrane is broken down and cast off in the form of minute shreds, a fresh mucous membrane being developed in the interval between two periods. During this process the capillary network would be laid bare and ruptured, and the escape of blood readily accounted for. Tyler Smith, who adopted this theory, states that he has frequently seen the uterine mucous membrane, in women who have died during menstruation, in a state of dissolution, with the broken loops of the capillaries exposed. The phenomena attending the so-called membranous dysmenorrhoea, in which the mucous membrane is thrown off in shreds, or as a cast of the uterine cavity-the nature of which was first pointed out by Simpson and Oldham-have been supposed to corroborate this theory. This view is, in the main, corroborated by the recent researches of Engelmann, Williams, and others. Williams describes the mucous lining of the uterus as undergoing a fatty degeneration before each period, which commences near the inner os, and extends over the whole mucous membrane, and down to the muscular wall. This seems to bring on a certain amount of muscular contraction, which drives the blood into the capillaries of the mucosa, and these, having become degenerated, readily rupture, and permit the escape of the blood. The mucous membrane now rapidly disintegrates, and is cast off in shreds with the menstrual discharge, in which masses of epithelial cells may always be detected. Engelmann, however, holds that the fatty degeneration is limited to the superficial layers, and that a portion only of the epithelial investment is thrown off. As soon as the period is over, the formation of a new mucous membrane is begun, which arises either from proliferation of the elements of the muscular coat itself, or from the proliferation of the epithelial cells lining the bases of the uterine glands which remain imbedded in the muscular tissue after the mucous membrane has been thrown off, and at the end of a week the whole uterine cavity is lined by a thin mucous membrane. This grows until the advent of another period, when the same degenerative changes occur unless impregnation has taken place, in which case it becomes further developed into the decidua. Lowenthal believes that the menstrual decidua is produced by the imbedding of an ovum in the lining membrane of the uterus, which, if impregnation occurs, is developed into the decidua of pregnancy. If conception does not take place, the ovum dies, and this is followed by the degeneration and expulsion of the menstrual decidua, accompanied by a flow of blood, which is the menstrual discharge.

Theory of Menstruation.-That there is an intimate connection. between ovulation and menstruation is admitted by most physiologists, and it is held by many that the determining cause of the discharge is the periodic maturation of the Graafian follicles. There is abundant.

1 American Journal of Obstetrics, 1875-76, vol. viii. p. 30.

D. 496.

"On the Structure of the Mucous Membrane of the Uterus," Obstet. Journ., 1875-76, vol. iii. 3 Arch. f. Gyn., Bd. xxiv., Heft 2, S. 169: Eine neue Deutung des Menstruations-Prozess.”

evidence of this connection, for we know that when, at the change of life, the Graafian follicles cease to develop, menstruation is arrested ; and when the ovaries are removed by operation, of which there are now numerous cases on record, or when they are congenitally absent, menstruation does not generally take place. A few cases, however, have been observed in which menstruation continued after double ovariotomy, or the removal of the ovaries by Battey's operation, and these have been used as an argument by those physiologists who doubt the ovular theory of menstruation. Slavyansky has particularly insisted on such cases, which, however, are probably susceptible of explanation. It may be that the habit of menstruation may continue for a time even after the removal of the ovaries; and it has not been shown that menstruation has continued permanently after double ovariotomy, although it certainly has occasionally, although quite exceptionally, done so for a time. It is possible, also, that in such cases a small portion of ovarian tissue may have been left unremoved, sufficient to carry on ovulation. Roberts, a traveller quoted by Depaul and Guéniot in their article on Menstruation in the Dictionnaire des Sciences Médicales, relates that in certain parts of Central Asia it is the custom to remove both ovaries in young girls who act as guards to the harems. These women, known as "hedjeras," subsequently assume much of the virile type, and never menstruate. The same close connection between ovulation and the rut of animals is observed, and supports the conclusion that the rut and menstruation are analogous. The chief difference between ovulation in man and the lower animals is that in the latter the process is not generally accompanied by a sanguineous flow. To this there are exceptions, for in monkeys there is certainly a discharge analogous to menstruation occurring at intervals.

Another point of distinction is that in animals connection never takes place except during the rut, and that it is then only that the female is capable of conception; while in the human race conception only occurs in the interval between the periods. This is another argument brought against the ovular theory, because, it is said, if menstruation depend on the rupture of a Graafian follicle and the emission of an ovule, then impregnation should only take place during or immediately after menstruation. Coste explains this by supposing that it is the maturation and not the rupture of the follicle which determines the occurrence of menstruation; and that the follicle may remain unruptured for a considerable time after it is mature, the escape of the ovule being subsequently determined by some accidental cause such as sexual excitement. However this may be, there is good reason to believe that the susceptibility to conception is greater during the menstrual epochs. Raciborski believes that in the large proportion of cases impregnation occurs in the first half of the menstrual interval, or in the few days immediately preceding the appearance of the discharge. There are, however, very numerous exceptions, for in Jewesses, who almost invariably live apart from their husbands for eight days after the cessation of menstruation, impregnation must constantly occur at some other period of the interval, and it is certain that they are not less prolific than other people. This rule with them is very strictly adhered to, as

will be seen by the accompanying interesting letter from a medical friend who is a well-known member of that community, and which I have permission to publish.' This fact is of itself sufficient to disprove the theory advanced by Dr. Avrard," that impregnation is impossible in the latter half of the menstrual interval. This, and the other reasons referred to, undoubtedly throw some doubt on the ovular theory, but they do not seem to be sufficient to justify the conclusion that menstruation is a physiological process altogether independent of the development and maturation of the Graafian follicles. All that they can be fairly held to prove is that the escape of the ovules may occur independently of menstruation, but the weight of evidence remains strongly in favor of the theory which is generally received.

3

It should be stated that several recent writers, Lawson Tait amongst the number, attribute considerable influence in menstruation to the Fallopian tubes. Robinson, of Chicago, in an interesting paper, contends that menstruation is governed by nervous ganglia situated in the walls of the Fallopian tubes and uterus, which he calls "automatic menstrual ganglia.' These he considers to be analogous to the nerve ganglia found in the heart, intestines, and other hollow viscera, and to have the function of producing rhythmical peristalsis in the tubes, which favors the passage of the ovum along their canal. He believes that ovulation is entirely unconnected with menstruation, and goes on independently of it, the greater part of the ovules being lost in the peritoneal cavity; and that it is only when the periodic and rhythmical action of the tubes begins that menstruation is established. These views cannot be taken as proved, but they certainly suggest an explanation of some of the phenomena of menstruation otherwise difficult to understand, such as its occasional continuance after the removal of the ovaries, and are well worthy of further investigation.

The cause of the monthly periodicity is quite unknown, and will probably always remain so. Goodman has suggested what he calls the "cyclical theory of menstruation," which refers the phenomena to a

1 10 BERNARD STREET, RUSSELL SQUARE, July 21, 1873.

MY DEAR SIR: 1. To the best of my knowledge and belief the law which prohibits sexual intercourse among Jews for seven clear days after the cessation of menstruation, is almost universally observed, the exceptions not being sufficient to vitiate statistics. The law has perhaps fewer exceptions on the Continent-especially Russia and Poland, where the Jewish population is very great-than in England. Even here, however, women who observe no other ceremonial law observe this, and cling to it after everything else is thrown overboard. There are doubtless many exceptions, especially among the better classes in England, who keep only three days after the cessation of the menses.

2. The law is-as you state-that should the discharge last only an hour or so, or should there be only one gush or one spot on the linen, the five days during which the period might continue are observed; to which must be superadded the seven clear days-twelve days per mensem in which connection is disallowed. Should any discharge be seen in the inter-menstrual period, seven days would have to be kept, but not the five, for such irregular discharge.

3. The "bath of purification," which must contain at least eighty gallons, is used on the last night of the seven clear days. It is not used till after a bath for cleansing purposes; and, from the night when such "purifying" bath is used, Jewish women are accustomed to calculate the Commencement of pregnancy. That you should not have heard it is not strange; its mention would be considered highly indelicate.

4. Jewish women reckon their pregnancy to last nine calendar or ten lunar months-270 to 280 days. There are no special data on which to reckon an average, nor do I know of any books on the subject, except some Talmu lic authorities, which I will look up for you if you desire it. Pray make no apologies for writing to me: any information I possess is at your service. I am, dear Sir, yours very truly,

DR. PLAYFAIR.

A. ASHER.

P. S.-The Biblical foundation for the law of the seven clear days is Leviticus xv., verse 19 till the end of the chapter-especially verse 28.

Rev. de Thérap. Méd.-Chir., 1867.

3 American Journal of Obstetrics, Sept. 1891.

4 Ibid., 1878, vol. xi. p. 673.

general condition of the vascular system, specially localizing itself in the generative organs, and connected with rhythmical changes in their nerve-centres. It does not seem to me, however, that he has satisfactorily proved the recurrence of the conditions which his ingenious theory assumes. The purpose of the loss of so much blood is also semewhat obscure. To a certain extent it must be considered an accident or complication of ovulation, produced by the vascular turgescence. Nor is it essential to fecundation, because women often conceive during lactation, when menstruation is suspended; or before the function has become established. It may, however, serve the negative purpose of relieving the congested uterine capillaries which are periodically filled with a supply of blood for the great growth which takes place when conception has occurred. Thus, immediately before each period the uterus may be considered to be placed by the afflux of blood in a state of preparation for the function it may suddenly be called upon to perform. That the discharge relieves a state of vascular tension which accompanies ovulation is proved by the singular phenomenon of vicarious menstruation which is occasionally, though rarely, met with. It occurs in cases in which, from some unexplained cause, the discharge does not escape from the uterine mucous membrane. Under such circumstances a more or less regular escape of blood may take place from other sites. The most common situations are the mucous membranes of the stomach, of the nasal cavities, or of the lungs; the skin, not uncommonly that of the mamma, probably on account of their intimate sympathetic relation with the uterine organs; from the surface of an ulcer; or from hemorrhoids. It is a noteworthy fact that in all these cases the discharge occurs in situations where its external escape can readily take place. This strange deviation of the menstrual discharge may be taken as a sign of general ill-health, and it is usually met with in delicate young women of highly mobile nervous constitution. It may, however, begin at puberty, and it has even been observed during the whole sexual life. The recurrence is regular, and always in connection with the menstrual nisus, although the amount of blood lost is much less than in ordinary menstruation.

Cessation of Menstruation.-After a certain time changes occur, showing that the woman is no longer fitted for reproduction; menstruation ceases, Graafian follicles are no longer matured, and the ovary becomes shrivelled and wrinkled on its surface. Analogous alterations take place in the uterus and its appendages. The Fallopian tubes atrophy, and are not unfrequently obliterated. The uterus decreases in size. The cervix undergoes a remarkable change, which is readily detected on vaginal examination; the projection of the cervix into the vaginal canal disappears, and the orifice of the os uteri in oll women is found to be flush with the roof of the vagina. In a large number of cases there is, after the cessation of menstruation, an occlusion both of the external and internal os; the canal of the cervix between them, however, remains patulous, and is not unfrequently distended with a mucous secretion.

Period of Cessation.—The age at which menstruation ceases varies much in different women. In certain cases it may cease at an unusually