ffers in that the factor which {113} repels femaleness produces
no visible effect, and its presence or absence can only be determined by
the introduction of a third factor, that for pigmentation.

This conception of the nature of the Brown Leghorn hen leads to a curious
paradox. We have stated that the Silky cock transmits the pigmented
condition, but transmits it to his daughters only. Apparently the case is
one of unequal transmission by the father. Actually, as our analysis has
shown, it is one of unequal transmission by the mother, the father's
contribution to the offspring being identical for each sex. The mother
transmits to the daughters her dominant quality of femaleness, but to
balance this, as it were, she transmits to her sons another quality which
her daughters do not receive. It is a matter of common experience among
human families that in respect to particular qualities the sons tend to
resemble their mothers more than the daughters do, and it is not improbable
that such observations have a real foundation for which the clue may be
provided by the Brown Leghorn hen.

Nor is this the only reflection that the Brown Leghorn suggests. Owing to
the repulsion between the factors for femaleness and for pigment
inhibition, it is impossible by any form of mating to make a hen which is
homozygous for the inhibitor factor. She has bartered away for femaleness
the possibility of ever receiving a double dose of this factor. We know
that in some cases, as, for example, {114} that of the blue Andalusian
fowl, the qualities of the individual are markedly different according as
to whether he or she has received a single or a double dose of a given
factor. It is not inconceivable that some of the qualities in which a man
differs from a woman are founded upon a distinction of this nature. Certain
qualities of intellect, for example, may depend upon the existence in the
individual of a double dose of some factor which is repelled by femaleness.
If this is so, and if woman is bent upon achieving the results which such
qualities of intellect imply, it is not education or training that will
help her. Her problem is to get the factor on which the quality depends
into an ovum that carries also the factor for femaleness.

* * * * *

{115}

CHAPTER XI

SEX (_continued_)

The cases which we have considered in the last chapter belong to a group in
which the peculiarities of inheritance are most