ified, as beautifully adapted for various purposes, and as
excellently co-ordinated as we see in the animals and plants around us.
Hence Darwin regards selection as the paramount power, whether applied
by man to the formation of domestic beings or by nature to the
production of species. Employing a favorite metaphor, he said: "If an
architect were to rear a noble and commodious edifice without the use of
cut stone, by selecting from the fragments at the base of a precipice
wedge-form stones for his arches, elongated stones for his lintels, and
flat stones for his roof, we should admire his skill and regard him as
the paramount power. Now, the fragments of stone, though indispensable
to the architect, bear to the edifice built by him the same relation
which the fluctuating variations of organic beings bear to the varied
and admirable structures ultimately acquired by their modified
descendants."

Some critics of the Darwinian theory of the origin of species have
declared that natural selection explains nothing, unless the precise
cause of each slight individual difference be made clear. Darwin rejoins
that if it were explained to a savage utterly ignorant of the art of
building how the edifice had been raised, stone upon stone, and why
wedge-formed fragments were used for the arches, flat stones for the
roof, etc.; and if the use of each part and of the whole building were
pointed out,--it would be unreasonable if he declared that nothing had
been made clear to him, because the precise cause of the shape of each
fragment could not be told. This, in Darwin's opinion, is a nearly
parallel case, with the objection that selection explains nothing
because we know not the cause of each individual difference in the
structure of each being. The shape of the fragments of stone at the base
of the hypothetical precipice may be called accidental, but the term is
not strictly applicable; for the shape of each depends on a long
sequence of events, all obeying natural laws; on the nature of the rock,
on the lines of deposition or cleavage, on the form of the mountain,
which depends on its upheaval and subsequent denudation, and, lastly,
on the storm or earthquake which throws down the fragments.

In regard to the use, however, to which the fragments may be put, their
shape may be strictly said to be accidental. Here Darwin acknowledged
that we are brought face to face with a great difficulty in alluding to
which he felt that he was tr