remains barren. Facts of this kind destroy the value of the supposed
criterion.

If, weary of the endless difficulties involved in the determination of
species, the investigator, contenting himself with the rough practical
distinction of separable kinds, endeavours to study them as they occur in
nature--to ascertain their relations to the conditions which surround them,
their mutual harmonies and discordancies of structure, the bond of union of
their present and their past history, he finds himself, according to the
received notions, in a mighty maze, and with, at most, the dimmest
adumbration of a plan. If he starts with any one clear conviction, it is
that every part of a living creature is cunningly adapted to some special
use in its life. Has not his Paley told him that that seemingly useless
organ, the spleen, is beautifully adjusted as so much packing between the
other organs? And yet, at the outset of his studies, he finds that no
adaptive reason whatsoever can be given for one-half of the peculiarities
of vegetable structure. He also discovers rudimentary teeth, which are
never used, in the gums of the young calf and in those of the foetal whale;
insects which never bite have rudimental jaws, and others which never fly
have rudimental wings; naturally blind creatures have rudimental eyes; and
the halt have rudimentary limbs. So, again, no animal or plant puts on its
perfect form at once, but all have to start from the same point, however
various the course which each has to pursue. Not only men and horses, and
cats and dogs, lobsters and beetles, periwinkles and mussels, but even the
very sponges and animalcules commence their existence under forms which are
essentially undistinguishable; and this is true of all the infinite variety
of plants. Nay, more, all living beings march, side by side, along the high
road of development, and separate the later the more like they are; like
people leaving church, who all go down the aisle, but having reached the
door, some turn into the parsonage, others go down the village, and others