subjected.
Despite the contempt with which Darwin referred to Lamarck’s theory, he
himself, as we have seen, often made use of the principle of the
inheritance of acquired characters, and even employed the same
illustrations cited by Lamarck. Darwin seems to have misunderstood
Lamarck’s view, and to have accepted the current opinion that Lamarck
supposed an animal acquired a new organ by desiring or needing it.
Darwin says, “Heaven forefend me from Lamarck’s nonsense of a tendency
to progressive adaptation from the slow willing of the animals.” Darwin
speaks of Lamarck as stating that animals will that the egg shall be a
particular form so as to become attached to particular objects.
Lamarck’s latest biographer, Packard, says he is unable to find any
statements of this sort in Lamarck’s writings.
The following cases that Darwin tried to explain through the inheritance
of acquired characters are exactly like those to which Lamarck applied
his theory. The bones of the wing of the domestic duck weigh less than
those of the wild duck, and the bones of the leg more. Darwin believes
this is due to the effects of the inheritance of acquired characters.
The drooping ears of many domestic mammals are also explained by him as
a result of disuse—“the animals being seldom much alarmed.” In speaking
of the male of the beetle, _Onites apelles_, Darwin quotes Kirby to the
effect that the tarsi are so habitually lost that the species has been
described without this part of the foot. In the sacred beetle of Egypt
the tarsus is totally absent. Hence he concludes that the absence of
tarsi in the sacred beetle, and the rudimentary condition of the tarsus
in others, is probably the result of disuse, rather than a case of
inheritance of a mutilation. Darwin grants that “the evidence that
accidental mutilations can be inherited is at present not decisive, but
the remarkable case observed by Brown-Séquard in guinea-pigs of the
inherited effects of operations should make us cautious in denying this
tendency.”
The wingless condition of several insects inhabiting oceanic islands has
come about, Darwin thinks, through disuse. The ostrich also, owing to
its increase in size, made less use of its wings and more use of its
legs, with the result that its wings degenerated and its legs got
stronger. The rudimentary condition of the eyes of the mole is the
result of disuse, “aided perhaps by natural selection.” Many of the
animals inhabiting the caves of Kentucky and of Carniola are blind, and
this is ascribed to disuse. “As it is difficult to imagine that the
eyes, though useless, could be in any way injurious to animals living in
darkness, their loss may be attributed to disuse.” The long neck of the
giraffe Darwin attributes partly to natural selection and partly to use.
Public-domain text, read in full here on John Shaqi.
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