equal plainness that these rudimentary or atrophied organs, are
imperfect and useless. In works on natural history rudimentary organs
are generally said to have been created for the sake of symmetry, or
in order to complete the scheme of nature; but this seems to me no
explanation, merely a restatement of the fact. Would it be thought
sufficient to say that because planets revolve in elliptic courses
round the sun, satellites follow the same course round the planets, for
the sake of symmetry, and to complete the scheme of nature? An eminent
physiologist accounts for the presence of rudimentary organs, by
supposing that they serve to excrete matter in excess, or injurious to
the system; but can we suppose that the minute papilla, which often
represents the pistil in male flowers, and which is formed merely of
cellular tissue, can thus act? Can we suppose that the formation of
rudimentary teeth which are subsequently absorbed, can be of any
service to the rapidly growing embryonic calf by the excretion of
precious phosphate of lime? When a man s fingers have been amputated,
imperfect nails sometimes appear on the stumps: I could as soon believe
that these vestiges of nails have appeared, not from unknown laws
of growth, but in order to excrete horny matter, as that the
rudimentary nails on the fin of the manatee were formed for this
purpose.
On my view of descent with modification, the origin of rudimentary
organs is simple. We have plenty of cases of rudimentary organs in our
domestic productions, as the stump of a tail in tailless breeds, the
vestige of an ear in earless breeds, the reappearance of minute
dangling horns in hornless breeds of cattle, more especially, according
to Youatt, in young animals, and the state of the whole flower in the
cauliflower. We often see rudiments of various parts in monsters. But I
doubt whether any of these cases throw light on the origin of
rudimentary organs in a state of nature, further than by showing that
rudiments can be produced; for I doubt whether species under nature
ever undergo abrupt changes. I believe that disuse has been the main
agency; that it has led in successive generations to the gradual
reduction of various organs, until they have become rudimentary, as in
the case of the eyes of animals inhabiting dark caverns, and of the
wings of birds inhabiting oceanic islands, which have seldom been
forced to take flight, and have ultimately lost the power of flying.
Again, an organ useful under certain conditions, might become injurious
under others, as with the wings of beetles living on small and exposed
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