the failure to do so. The stumbling-blocks are various, and they lie in
every path: we can allude only to one or two as specimens.

Adaptation and utility are the marks of design. What, then, are organs not
adapted to use marks of? Functionless organs of some sort are the heritage
of almost every species. We have ways of seeming to account for them--and
of late one which may really account for them--but they are unaccountable
on the principle of design. Some, shutting their eyes to the difficulty,
deny that we know them to be functionless, and prefer to believe they must
have a use because they exist, and are more or less connected with organs
which are correlated to obvious use; but only blindfolded persons care to
tread the round of so narrow a circle. Of late some such abortive organs in
flowers and fruits are found to have a use, though not the use of their
kind. But unwavering believers in design should not trust too much to
instances of this sort. There is an old adage that, if anything be kept
long enough, a use will be found for it. If the following up of this line,
when it comes in our way, should bring us round again to a teleological
principle, it will not be one which conforms to the prevalent ideas now
attacked.

It is commonly said that abortive and useless organs exist for the sake of
symmetry, or as parts of a plan. To say this, and stop there, is a fine
instance of mere seeming to say something. For, under the principle of
design, what is the sense of introducing useless parts into a useful
organism, and what shadow of explanation does "symmetry" give? To go
further and explain the cause of the symmetry and how abortive organs came
to be, is more to the purpose, but it introduces quite another principle
than that of design. The difficulty recurs in a somewhat different form
when an organ is useful and of exquisite perfection in some species, but
functionless in another. An organ, such as an eye, strikes us by its