galton.org 199
Selection and Race
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The causes that check the unlimited improvement of highly-bred animals,
so long as the race remains unchanged, are many and absolute.
In the first place there is an increasing delicacy of constitution; the
growing fineness of limb and structure end, after a few generations, in
fragility. Overbred animals have little stamina; they resemble in this
respect the “weedy” colts so often reared from first-class racers. One can
perhaps see in a general way why this should be so. Each individual is the
outcome of a vast number of organic elements of the most various species,
just as some nation-might be the outcome of a vast number of castes of
individuals, each caste monopolising a special pursuit. Banish a number
of the humbler castes—the bakers, the bricklayers, and the smiths, and the
nation would soon come to grief. This is what is done in high breeding;
certain qualities are bred for, and the rest are diminished as far as possible,
but they cannot be dispensed with entirely.
The next difficulty lies in the diminished fertility of highly-bred
animals. It is not improbable that its cause is of the same character as that
of the delicacy of their constitution. Together with infertility is combined
some degree of sexual indifference, or when passion is shown, it is not
unfrequently for some specimen of a coarser type. This is certainly the
case with horses and with dogs.
It will be easily understood that these difficulties, which are so
formidable in the case of plants and animals, which we can mate as we
please and destroy when we please, would make the maintenance of a
highly-selected breed of men an impossibility.
Whenever a low race is preserved under conditions of life that exact a
high level of efficiency, it must be subjected to rigorous selection. The
few best specimens of that race can alone be allowed to become parents,
and not many of their descendants can be allowed to live. On the other
hand; if a higher race be substituted for the low one, all this terrible
misery disappears. The most merciful form of what I ventured to call
“eugenics” would consist in watching for the indications of superior
strains or races, and in so favoring them that their progeny shall
outnumber and gradually
