stature, and _vice versa_. What is commonly known as menstruation lasts
only a few days, and is merely the critical period in a monthly cycle or
periodicity which goes with the female sex specialization. This period
involves the gradual preparation of the uterus or womb for a guest,
together with the maturing of the ova. Then the Graafian follicles
containing the ova break and these latter enter the uterus for
fertilization.

If fertilization takes place, the fertilized egg buries itself in the
wall and development of the embryo proceeds. Menstruation stops, the
calcium salts being required for the growing embryo. There is likely to
be no menstruation for a considerable time after delivery if the child
is nursed, as is normal. This gives the uterus time for devolution to
the normal, before a surplus of calcium salts sets the periodicity going
again. If the egg which passes from the ovary to the uterus is not
fertilized, it is excreted, the uterus goes through another monthly
cycle of preparation for the period of intra-maternal environment, and
so on indefinitely until the climacteric.

This climacteric or decay of sexuality is a rather critical time,
especially in women. It marks the period at which the metabolism can no
longer support the strain of reproduction. A surplus of calcium brings
on senility, as noted above. Withdrawal of the interests which centre in
sex, together with the marked accompanying physical changes, involves a
shift of mental attitude which is also frequently serious. A British
coroner stated in the _British Medical Journal_ in 1900 (Vol. 2, p.792)
that a majority of 200 cases of female suicide occurred at this period,
while in the case of younger women suicide is peculiarly likely to occur
during menstruation. Krugelstein and Lombroso, respectively, remark the
same tendencies.[18]