internal secretions possible and actual. When we speak of the feminine
we really mean the predominantly feminine. And when we speak of
the masculine, we mean the mainly masculine. Between, all sorts of
transitions are possible and occur.

Man in relation to the internal secretions we have considered in
reviewing the interstitial cells. To him, we shall return later. Let
us turn now to that fascinating subject of the ages, Woman. What
produces and maintains the Feminine?

THE CAUSE OF SEX

To all appearances, that inscrutable simplest of living things, the
fertilized ovum, beginning of the human, starts bisexual, double
sexed, both masculine and feminine, or perhaps neither masculine nor
feminine. Then a form develops. Then within that form a patch of cells
arise which the microscopist recognizes as the forerunners of the male
or the female reproductive cells. Then some more development. And at
birth, sex is definitely settled, as far as the reproductive organs
are concerned.

Our knowledge here, as everywhere, is still fragmentary. Statistical
reviews seem to show that in times of stress, war, famine, pestilence,
more boys are born than girls. But that is neither here nor there. It
sheds no further light on the subject. Monosexuality is a distinction
of the human species: the sexes are pretty clearly differentiated.
In some animals, such as some worms, there is a bisexuality of the
individual. There are present the reproductive organs of both sexes,
capable of impregnating other individuals as well as of being
impregnated. In some of these, even self-impregnation may occur. This
is the condition of hermaphroditism.

But the higher up one goes in the scale of evolution, the greater
becomes the distinction between the sexes. Anatomic hermaphroditism
becomes a rare anomaly. Life appears to have perfected this trick of
separate sexes, sex specialization, in short, for the sake of the
efficiency which goes with specialization.

When a germ cell divides, its nuclear material breaks up into segments
known as chromosomes. Now it has been found, for example in the case
of the common squash bug, anasa tristis, that there are 22 chromosomes
in the female, and 21 in the male. In the female two of these are
visibly different from the rest, while in the male there is one odd
one, the remaining 20 being like the corresponding 20 of the female.
Before the germ cell becomes fit to mix with a germ cell of opposite
sex, in the p