EUGENICS AND SOCIETY
untrained in the children from lower social strata. Contrary to usual
belief, only about a third of the children whose performance is in the
top thousandth, come from the higher social and the professional
classes, while wage-earners contribute 50 per cent, of these children
of "exceptional intelligence." Thus our society is not utilizing the
innate intelligence of its members as it might, nor does the system
give adequate opportunity for intelligence to rise.
Again, highly-strung types are less likely to achieve success in the
lower economic strata, more likely to become neurotic or insane.
People from the lower-middle and working classes who are apparently
mentally deficient or abnormal have often reached their unfortunate
condition because they have not had either the care or the oppor-
tunities for self-expression which would have been available in a more
generous social environment.
Let us also remember that society as a whole can have a similar
effect. Those same types which in Siberian tribes would achieve
prestige and power as shamans and medicine-men, or in the medieval
world would have become candidates for sainthood, would here and
to-day often find their way into asylums.
This brings us on to a biological point whose importance has not
always been realized. It is that selection is theoretically meaningless
and practically without value except in relation to a particular en-
vironment. The practical implications are both the easiest to grasp
and the more important for our purpose. In breeding domestic
animals, as Hammond of Cambridge has so well stressed,1 selection
and breeding will not produce the desired results so quickly, and may
not produce them at all, if they are conducted in the unreal environ-
ment of an academic breeding station where optimum conditions are
provided. They should be conducted in an environment similar to
that in which the animals are destined to be used.
An extreme illustration of this is provided by cattle. In various
parts of tropical Africa, the semi-arid bush country provides but
scanty nutriment, and erosion has led to various mineral deficiencies,
The native cattle are scrubby little beasts, no bigger than ponies,
yielding not more than two gallons of milk a day, and growing so
slowly that they do not breed until four or five years old. Contrasted
with cows of a good modern British milking breed, which are double
the size, give up to nine gallons of milk daily, and breed at two to
three years of age, they are, you would say, very inefficient bits of
biological machinery. Yet if we try to introduce European breeds
into such areas, they are a complete failure. They make demands
1 Hammond, 1932 (pp. 351-2), 1935.