Another matter which disturbs the woman at this time, in many cases, is the common belief that after "the change" she will lose all of her sex attractiveness, and her sexual feelings, etc. This is a grave error, for the experience of all observing physicians is that no such results follow this period of the woman's life. Many women become even more attractive to the other sex after this time, by reason of acquiring a certain maturity and "ripeness" which proves very attractive to many men--often to young men as well as older ones. Moreover, the sexual desires do not cease with the cessation of the reproductive functions. On the contrary, it often happens that such emotions and desires are increased in the woman at, and after, this time of her life. So true is this that this period has been called "The Dangerous Age" for women, and the experience of many a woman of forty-five to fifty will corroborate this statement. The woman at this time should beware of contracting unwise love affairs and entanglements, and of yielding to impulses toward men other than her mate. A word to the wise should be sufficient in this case. To return to the main subject of Menstruation, it may be said that the monthly flow, when once established, occurs at intervals of every twenty-eight days, on the average, although in some individual cases it occurs as often as every twenty-one days, while in others it occurs as seldom as once in every six weeks, all without exceeding the bounds of normal functioning. Menstruation ceases temporarily during pregnancy, in normal cases, and often also ceases during the period of lactation or nursing. The menstrual period lasts on an average for four or five days, the flow increasing for the first half of the period, and decreasing during the last half. At the beginning of the period there is often manifested a general congestion of all of the sexual organs of the woman, and often of the breasts as well. There is also usually found a sense of physical discomfort, from which more or less irritable feeling arises. In rare cases there are found severe cramps and pains, and in some cases the woman finds it necessary to call in medical aid, or to go to bed, or both. In such cases a cure is often worked by improving the general health, and by observing common sense hygienic rules. Menstruation is caused by a hypertrophy of the mucus membrane of inner surface of the Uterus, which is followed by a shedding of the hypertrophied membrane. This leaves exposed the underlying vessels, which bleed. New mucus membrane is formed after the period. The menstrual flow consists of a thin, bloody fluid, having peculiar odor, in which is combined blood, thin skin, and mucus membrane, and also mucus from the Uterus and the Vagina, the blood being light in consistency and not clotted. During the menstrual period the ovum, or egg, is discharged, and enters the Uterus, as we shall see presently.