mber_ of parents and their offspring,--to treat the
problem by statistical methods.

But, it may be objected, a uniformity gained by such methods is
spurious. It is merely shutting the eyes to the mass of contradictions
which are concealed by an apparent statistical uniformity.

This objection would be valid, if the statistical results were used for
prediction _in individual cases_. The statistician, however, expressly
warns that his conclusions must not be used for such prediction. They
are intended to predict only general trends, only average results; and
for this purpose they are wholly legitimate. Moreover, evolution itself
is a problem of statistics, and therefore the statistical method of
studying heredity may offer results of great value to eugenics, even
though it can not furnish in individual cases the prediction which would
be desirable.

From this standpoint, we return to attack the problem of the relation
between parent and offspring. We noted that there is no uniform sequence
in a single family, and illustrated this by the case of brown eyes. But
if a thousand parents and their offspring be selected and some trait,
such as eye-color, or stature, or general intelligence, be measured, a
uniformity at once appears in the fact of regression. Its discoverer,
Sir Francis Galton, gives this account of it:

[Illustration: FINGER-PRINTS OF TWINS

FIG. 25.--Above are the finger-prints, supplied by J. H. Taylor
of the Navy Department, of the two young sailors shown in Fig. 24. The
reader might examine them once or twice without seeing any differences.
Systematic comparison reveals that the thumbs of the left hands and the
middle fingers of the right hands particularly are distinguishable.
Finger-prints as a means of identification were popularized by Sir
Francis Galton, the founder of eugenics, and their superiority to all
other methods is now generally admitted. In addition to this practical
usefulness, they also furnish material for study of the geneticist and
zooelogist. The extent to which heredity is responsible for the patterns
is indicated by the resemblance in pattern in spite of the great
variability in this tract.]

"If the word 'peculiarity' be used to signify the difference between the
amount of any faculty possessed by a man, and the average of that
possessed by the population at large, then the law of regression may
be described as follows: each peculiarity in a man is shared by his
kinsmen, but o