and to the
falcon. But you will find that it has still others to entirely another
world. As you watch it glance and skim over the surface of the waters,
has it never struck you what relation it bears to the creatures that
glance and glide _under_ their surface? Fly-catchers, some of
them, also,--fly-catchers in the same manner, with wide mouth; while in
motion the bird almost exactly combines the dart of the trout with the
dash of the dolphin, to the rounded forehead and projecting muzzle of
which its own bullet head and bill exactly correspond. In its plunge,
if you watch it bathing, you may see it dip its breast just as much
under the water as a porpoise shows its back above. You can only
rightly describe the bird by the resemblances, and images of what it
seems to have changed from,--then adding the fantastic and beautiful
contrast of the unimaginable change. It is an owl that has been trained
by the Graces. It is a bat that loves the morning light. It is the
aerial reflection of a dolphin. It is the tender domestication of a
trout.

63. And yet be assured, as it cannot have been all these creatures, so
it has never, in truth, been any of them. The transformations believed
in by the mythologists are at least spiritually true; you cannot too
carefully trace or too accurately consider them. But the
transformations believed in by the anatomist are as yet proved true in
no single instance, and in no substance, spiritual or material; and I
cannot too often, or too earnestly, urge you not to waste your time in
guessing what animals may once have been, while you remain in nearly
total ignorance of what they are.

64. Do you even know distinctly from each other,--(for that is the real
naturalist's business; instead of confounding them with each
other),--do you know distinctly the five great species of this familiar
bird?--the swallow, the house-martin, the sand-martin, the swift, and
the Alpine swift?--or can you so much as answer the first question
which would suggest itself to any careful observer of the form of its
most familiar species,--yet which I do not find proposed, far less
answered, in any scientific book,--namely, why a swallow has a
swallow-tail?

It is true that the tail feathers in many birds appear to be
entirely,--even cumbrously, decorative; as in the peacock, and birds of
paradise. But I am confident that it is not so in the swallow, and that
the forked tail, so defined in form and strong in plume, has