It hardly need be stated here, for it is a matter of common knowledge,
that the _primary_ purpose of sex in the human family is the
reproduction of the race. In this respect, considered merely on its
material, or animal side, mankind differs little from all other forms
of animate life. As Whitman says, we see "everywhere sex, everywhere
the urge of procreation." The flowers are possessed of this quality,
and with them all vegetable forms. In the animal kingdom the same is
true. Always "male and female" is everything created.

And the chief facts in reproduction are practically the same wherever
the phenomena occur. Here, as everywhere else in the world, when a
new life-form appears, it is always the result of the union of _two_
forces, elements, germs or whatsoever. These two elements differ
in nature and in function, and each is incomplete and worthless by
itself. It is only by the combining of the two that any new result
is obtained. It is this fact that has led to the most suggestive and
beautiful phrase "The duality of all unity in nature."

Many centuries ago an old Latin philosopher wrote the now celebrated
phrase, _Omne ex ovo_, which, translated, means _everything is from an
egg_. This is practically true of all life-forms. Their beginning
is always from an ovum, or egg. In this respect, the reproduction of
human beings is the same as that of any other life-form.

Now in this process of producing a new life-form, the female is always
the source of the egg, out of which the new creation is to come. This
egg, however, is infertile of itself, and must be given life to, by
mingling with its germ, an element which only the male can produce
and supply. This element is technically known as a sperm, or a
spermatozoa. Its function is to fertilize the dormant germ in the