hers, that the skeleton of the horse differs from that of the
human body. . . . We find ribs in man, in all the quadrupeds, in
birds, in fishes, and we may find traces of them as far down as the
turtle, in which they seem still to be sketched out by means of
furrows that are to be found beneath the shell. Let it be remembered
that the foot of the horse, which seems so different from a man's
hand, is, nevertheless, as M. Daubenton has pointed out, composed of
the same bones, and that we have at the end of each of our fingers a
nail corresponding to the hoof of a horse's foot. Judge, then,
whether this hidden resemblance is not more marvellous than any
outward differences--whether this constancy to a single plan of
structure which we may follow from man to the quadrupeds, from the
quadrupeds to the cetacea, from the cetacea to birds, from birds to
reptiles, from reptiles to fishes--in which all such essential parts
as heart, intestines, spine are invariably found--whether, I say, this
does not seem to indicate that the Creator when He made them would use
but a single main idea, though at the same time varying it in every
conceivable way, so that man might admire equally the magnificence of
the execution and the simplicity of the design." {174}

"If we regard the matter thus, not only the ass and the horse, _but
even man himself_, _the apes_, _the quadrupeds_, _and all animals
might be regarded but as forming members of one and the same family_.
But are we to conclude that within this vast family which the Creator
has called into existence out of nothing, there are other and smaller
families, projected as it were by Nature, and brought forth by her in
the natural course of events and after a long time, of which some
contain but two members, as the ass and the horse, others many
members, as the weasel, martin, stoat, ferret, &c., and that on the
same principle there are families of vegetables, containing ten,
twenty, or thirty plants, as the case may be? If such families had
any real existence they could have been formed only by crossing, by
the accumulation of successive variations (_variation successive_),
and by degeneration from an original type; but if we once admit that
there are families of plants and animals, so that the ass may be of
the family of the horse, and that the one may only differ from the
other thro