PUBERTY AND MENSTRUATION 435 



and birth of the new being. In case fertilization fail, the stimulating 

 material ceases to be produced and the uterus rids itself by menstruation 

 of the now useless growth in its mucosa (see below). Things fit 

 together too well on this hypothesis to warrant its rejection unless dis- 

 proved. None the less, at present it is a theory only. 



While it is true that the ovary probably discharges an ovum each lunar 

 month, the exact time-relation between this event and menstruation is 

 still a matter of research and discussion, a discussion which can be made 

 clearer when the facts and theory of menstruation have been given. 



MENSTRUATION is the monthly hemorrhage which occurs from the 

 uterus in women and in some of the higher apes. It occurs (but not 

 monthly) in the females of many other species, such as the equine, bovine, 

 and canine animals. It begins its periodical routine at puberty (as early 

 as the ninth year in Africa and as late as the seventeenth in Lapland), 

 and continues normally, except during the pregnancies and lactations, 

 until the menopause at the forty-fifth or fiftieth year. Some women, 

 but not many, menstruate throughout pregnancy; very rarely even fertile 

 women do not menstruate at all. Individual differences as regards 

 menstruation are great in the frequency, the amount of hemorrhage, 

 the duration, the ages of commencement and cessation, the secondary 

 phenomena, etc. On the average, however, the occurrences are as 

 follows : 



At intervals of twenty-eight days a flow of blood comes from the uterus 

 and continues for four or five days. Many women are unwell every three 

 weeks and fewer show an interval of thirty-two or thirty-three days, these 

 being the normal limits. The more civilized and "cultured" the woman 

 the more pronounced is the flow, it being much less in the savage races. 

 Preceding the actual hemorrhage there are apt to be many varied pre- 

 monitory signs of its approach : indefinite and irregular pains, chilliness, 

 nervous instability and irritability; in many women these signs of a 

 general stimulation of the nervous system are seen especially about a 

 week before the flow begins. The breasts are enlarged by the congestion 

 and made firmer and somewhat tender to the touch. The amount of 

 urea excreted becomes smaller. The bloody discharge begins very grad- 

 ually and is apt at first to be somewhat watery. In a day or so the flow 

 becomes established often with no little uterine and ovarian pain (dys- 

 menorrhea), continues more or less abundantly for one or two days, and 

 then in one or two days more gradually stops. The quantity of blood 

 ordinarily ranges between 100 and 200 c.c., but is often very scanty, 

 especially in anemic young women who have too little physical exercise. 

 Often, too, it is as much as 400 or 500 c.c. in amount. It is because of 

 this habitual loss of blood that women stand severe accidental hemorrhage 

 better than do men. In a degree the ancient Jewish notion of the cat- 

 amenia as a means of purification is physiologically justified, for many 

 women are "more normal" in many ways just after menstruation than 

 before. This relief doubtless originates reflexly in the decrease of the 

 congestion in the sexual apparatus and to a lesser extent in that of the 



