166 galton.org
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Inquiries into Human Faculty
cases—that is, in nearly one-half of them—these were described as
closely similar; in the remaining nineteen they were much alike, but
subject to certain named differences. These differences belonged almost
wholly to such groups of qualities as these: The one was the more
vigorous, fearless, energetic; the other was gentle, clinging, and timid; or
the one was more ardent, the other more calm and placid; or again, the
one was the more independent, original, and self-contained; the other the
more generous, hasty, and vivacious. In short, the difference was that of
intensity or energy in one or other of its protean forms; it did not extend
more deeply into the structure of the characters. The more vivacious
might be subdued by ill health, until he assumed the character of the
other; or the latter might be raised by excellent health to that of the
former. The difference was in the key-note, not in the melody.
It follows from what has been said concerning the similar dispositions
of the twins, the similarity in the associations of their ideas, of their
special ailments, and of their illnesses generally, that the resemblances are
not superficial, but extremely intimate. I have only two cases of a strong
bodily resemblance being accompanied by mental diversity, and one case
only of the converse kind. It must be remembered that the conditions
which govern extreme likeness between twins are not the same as those
between ordinary brothers and sisters, and that it would be incorrect to
conclude from what has just been said about the twins that mental and
bodily likeness are invariably co-ordinate, such being by no means the
case.
We are now in a position to understand that the phrase “close
similarity” is no exaggeration, and to realise the value of the evidence I
am about to adduce. Here are thirty-five cases of twins who were.” closely
alike” in body and mind when they were young, and who have been
reared exactly alike up to their early manhood and womanhood. Since
then the conditions of their lives have changed; what change of Nurture
has produced the most variation?
It was with no little interest that I searched the records of the thirty-
five cases for an answer; and they gave an answer that was not altogether
direct, but it was distinct, and not at all what I had expected. They showed
me that
