of unnecessary and improbable hypotheses. The main
explanation or source of the fallacy may be found in the fact that
natural selection frequently imitates some of the more obvious effects
of use and disuse.

MODERN RELIANCE ON USE-INHERITANCE MISPLACED.

Modern philanthropy--so far at least as it ever studies ultimate
results--constantly relies on this ill-founded belief as its
justification for ignoring the warnings of those who point out the
ultimately disastrous results of a systematic defiance or reversal of
the great law of natural selection. This reliance finds strong support
in Mr. Spencer's latest teachings, for he holds that the inheritance of
the effects of use and disuse takes place universally, and that it is
now "the chief factor" in the evolution of civilized man (pp. 35, 74,
iv)--natural selection being quite inadequate for the work of
progressive modification. Practically he abandons the hope of evolution
by natural selection, and substitutes the ideal of a nation being
"modified _en masse_ by transmission of the effects" of its institutions
and habits. Use-inheritance will "mould its members far more rapidly and
comprehensively" than can be effected by the survival of the fittest
alone.

But could we rely upon the aid of use-inheritance if it really were a
universal law and not a mere simulation of one? Let us consider some of
the features of this alleged factor of evolution, seeing that it is
henceforth to be our principal means of securing the improvement of our
species and our continued adaptation to the changing conditions of a
progressive civilization.

It is curiously uncertain and irregular in its action. It diminishes or
abolishes some structures (such as jaws or eyes) without correspondingly
diminishing or abolishing other equally disused and closely related
parts (such as teeth, or eye-stalks). It thickens ducks' leg-bones while
allowing them to shorten. It shortens the disused wing-bones of ducks
and the leg-bones of rabbits while allowing them to thicken; and yet in
other cases it greatly reduces the thickness of bones without shortening
them. It transmits tameness most powerfully in an animal which usually
cannot acquire it. It aids in webbing the feet of water-dogs, but fails
to web the feet of the water-hen or to remove the web in the feet of
upland geese.[72] It allows the disused fibula to retain a potentiality
of development fully equal to that possessed by the long-used tibia.