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way to a given stimulus ; and secondly, the development
of this predisposition, which may or may not take place,
according to circumstance. But—
“ Only one of the causes which produce any acquired character
can be transmitted—the one which was present before the character
itself appeared, viz., the predisposition. . . . It is quite immaterial
to the following generation whether such predisposition comes into
operation or not.”—(Essays upon Heredity, vol. z., ist ed., p. ijii)
“It also follows that those other characters which have been
acquired by the influence of special external conditions during the
lifetime of the parent cannot be transmitted at all.”—{Ibid. p. 267.)
No increment due to the realisation of the predisposition
can be inherited ; consequently each generation has an
identical starting-point:—
“ The hypothesis of the continuity of the germ plasm gives an
identical starting point to each successive generation, and thus
explains how it is that an identical product arises from all of them.”
—{Ibid. p. 168.)
Now, with respect to this theory, we may remark that,
if it were true, it would afford a most interesting explana
tion of the strictest fixity of species. We could then
understand why there should be no modification of struc
ture or increase of capacity in the race ; since whatever
might be acquired by one generation would be lost in
the act of transmission to the next. But this theory is
used by the advocate of organic evolution, and it is incum
bent upon him to explain the facts of nature in accordance
with his theory. There is a transmutation of species, there
is an increased facility of operation, as in the case of
instincts which have been developed in the race; and yet
it is asserted that the offspring inherit the same predis
position from age to age. This theory of “ predisposition ”
is no less fatal to the logical demands of the theory of
Natural Selection. If each successive generation has an