a circular form_;" into
which circles we will excuse ourselves from entering. It is a system as
confused as it is fantastic; and our author, who writes in general in a
clear and lucid manner, in vain attempts to present us with an
intelligible exposition of it. Arrange the animal creation how you will,
in a line or in circles, there is one fact open to every observer, that
however fine may be the gradations amongst the lower animals, the
difference between the higher animals is very distinctly marked. It is a
difference which does not at all accord with the hypothesis of our author,
"that the simplest and most primitive type gave birth to the type next
above it, and this again produced the next higher, and so on to the very
highest, the stages of advance being in all cases very small--namely, from
one species only to another; so that the phenomenon has always been of
simple and modest character." Whilst he confines himself to _mollusks_,
and suchlike obscure creatures, the phenomenon he supposes may not be very
startling; but when he ascends to the higher and larger animals, whose
forms and habits are well known to us--when he has to find a father for
the horse, the lion, the rhinoceros, the elephant--his phenomenon, we are
sure, will no longer retain its "simple and modest character."

Naturalists have observed, that there is a striking _uniformity of plan_
even amongst animals of very different habits, and which, perhaps, inhabit
different elements; they have remarked, that this uniformity is adhered to
even when it appears to answer no specific purpose, as when in the fin of
a whale the unbending bone bears the semblance of the jointed hand. This,
too, is pressed into the service of our author's hypothesis. It is a
curious fact. But if we say of it, that it appears to hint the existence
of _some law_, and to tempt the investigation of the physiologist, we
assign to it all the scientific importance that it can possibly deserve.

Some physiologists, we must be permitted to observe, have rather amused
themselves by a display of ingenuity, than profited science by their
discoveries of a _unity of structure_ in animals of the most opposite
description. It is easy to surprise the imagination by pointing out
unexpected resemblances, if all cases of diversity are at the same time
kept out of view. These writers will mention, for instance, that all
quadrupeds have uniformly _seven_ bones in the neck. The giraffe has no
more