Applied Eugenics | Page 9

point in the investigation can
never be reached, but a tremendously strong suspicion is at least
justified. Now if the degree of resemblance between the prevalence of
myopia in parents and that in children be directly measured, and if it be
found that when the parent has eye trouble the child also has it, then it
seems that a general knowledge of heredity should lead to the belief
that the difficulty lies there, and that an environmental cause for the
poor vision of the school child was being sought, when it was all the
time due almost entirely to heredity. This final step has not yet been

completed in an adequate way,[7] but the evidence, partly analogical,
gives every reason to believe in the soundness of the conclusion stated,
that in most cases the schoolboy must wear glasses because of his
heredity, not because of overstudy or any neglect on the part of his
parents to care for his eyes properly during his childhood.
[Illustration: WHY MEN GROW SHORT OR TALL
FIG. 4.--Pedigree charts of the two men shown in the preceding
illustration. Squares represent men and circles women; figures
underlined denote measurement in stocking feet. It is obvious from a
comparison of the ancestry of the two men that the short one comes
from a predominantly short family, while the tall one gains his height
likewise from heredity. The shortest individual in the right-hand chart
would have been accounted tall in the family represented on the left.
After A. F. Blakeslee.]
The extent to which the intelligence of school children is dependent on
defective physique and unfavorable home environment is an important
practical question, which David Heron of London attacked by the
methods we have outlined. He wanted to find out whether the healthy
children were the most intelligent. One is constantly hearing stories of
how the intelligence of school children has been improved by some
treatment which improved their general health, but these stories are
rarely presented in such a way as to contribute evidence of scientific
value. It was desirable to know what exact measurement would show.
The intelligence of all the children in fourteen schools was measured in
its correlation with weight and height, conditions of clothing and teeth,
state of nutrition, cleanliness, good hearing, and the condition of the
cervical glands, tonsils and adenoids. It could not be found that mental
capacity was closely related to any of the characters dealt with.[8] The
particular set of characters measured was taken because it happened to
be furnished by data collected for another purpose; the various items
are suggestive rather than directly conclusive. Here again, the
correlation in most cases was less than .1, as compared with the general
heredity correlation of .5.
The investigation need not be limited to problems of bad breeding.

Eugenics, as its name shows, is primarily interested in "good breeding;"
it is particularly worth while, therefore, to examine the relations
between heredity and environment in the production of mental and
moral superiority.
If success in life--the kind of success that is due to great mental and
moral superiority--is due to the opportunities a man has, then it ought
to be pretty evenly distributed among all persons who have had
favorable opportunities, provided a large enough number of persons be
taken to allow the laws of probability full play. England offers a good
field to investigate this point, because Oxford and Cambridge, her two
great universities, turn out most of the eminent men of the country, or
at least have done so until recently. If nothing more is necessary to
ensure a youth's success than to give him a first-class education and the
chance to associate with superior people, then the prizes of life ought to
be pretty evenly distributed among the graduates of the two universities,
during a period of a century or two.
This is not the case. When we look at the history of England, as Galton
did nearly half a century ago, we find success in life to an unexpected
degree a family affair. The distinguished father is likely to have a
distinguished son, while the son of two "nobodies" has a very small
chance of becoming distinguished. To cite one concrete case, Galton
found[9] that the son of a distinguished judge had about one chance in
four of becoming himself distinguished, while the son of a man picked
out at random from the population had about one chance in 4,000 of
becoming similarly distinguished.
The objection at once occurs that perhaps social opportunities might
play the predominant part; that the son of an obscure man never gets a
chance, while the son of the prominent man is pushed forward
regardless of his inherent abilities. This, as Galton argued at length, can
not be true of men of really eminent attainments.