one before.
This is misleading. The handing on of such knowledge has nothing more to do
with heredity in the biological sense than has the handing on from parent
to offspring of a picture, or a title, or a pair of boots. All these things
are but the transfer from zygote to zygote of something extrinsic to the
species. Heredity, on the other hand, deals with the {183} transmission of
something intrinsic from gamete to zygote and from zygote to gamete. It is
the participation of the gamete in the process that is our criterion of
what is and what is not heredity.

Better hygiene and better education, then, are good for the zygote, because
they help him to make the fullest use of his inherent qualities. But the
qualities themselves remain unchanged in so far as the gamete is concerned,
since the gamete pays no heed to the intellectual development of the zygote
in whom he happens to dwell. Nevertheless, upon the gamete depend those
inherent faculties which enable the zygote to profit by his opportunities,
and, unless the zygote has received them from the gamete, the advantages of
education are of little worth. If we are bent upon producing a permanent
betterment that shall be independent of external circumstances, if we wish
the national stock to become inherently more vigorous in mind and body,
more free from congenital physical defect and feeble mentality, better able
to assimilate and act upon the stores of knowledge which have been
accumulated through the centuries, then it is the gamete that we must
consult. The saving grace is with the gamete, and with the gamete alone.

People generally look upon the human species as having two kinds of
individuals, males and females, and it is for them that the sociologists
and legislators frame their schemes. This, however, is but an imperfect
view to {184} take of ourselves. In reality we are of four kinds, male
zygotes and female zygotes, large gametes and small gametes, and heredity
is the link that binds us together. If our lives were like those of the
starfish or the sea-urchin, we should probably have realised this sooner.
For the gametes of these animals live freely, and contract their marriages
in the waters of the sea. With us it is different, because half of us must
live within the other half or perish. Parasites upon the rest, levying a
daily toll of nutriment upon their hosts, they are yet in some measure the
arbiters of the destiny of those within whom they dwell. At the