II.--PRACTICAL METHODS OF PREVENTION.

A. FOR WOMEN:

SEXUAL REPRODUCTION.


To understand the practical methods of birth-control, or the control of
conception, we must first have a clear view of the processes involved when
the reproductive organs are in activity, and of the nature and situation
of the sexual organs themselves. The diagrams on pages 34, 35 and 36 show
in general outline the reproductive organs of man and woman.

Now fertilisation does not necessarily occur whenever the male organ comes
in contact with the female organ. Fertilisation occurs only when a
male-cell (spermatazoon) unites with a female-cell (ovum); in other words,
when the spermatazoa in the seminal fluid of a man meet and unite with the
germ or ovum in the body of a woman. That is the beginning of the child.
This union of the two cells need not take place during or immediately
after sexual intercourse. It may occur many hours, or even two or three
weeks, after connection, because the spermatazoa have motion of their own.
They are tiny threadlike bodies, which may work their way towards the
ovum long after they have left the body of the man and been placed in the
body of the woman, and the uterus has a searching movement, and may by its
pulsations draw the spermatazoa upwards. For these reasons a woman cannot
be quite sure of the exact time of fertilisation, and hence cannot predict
exactly the date of the child-birth. Generally the pregnancy lasts nine