vegetable kingdoms, of an ascending scale of being, from simply
organized forms and imperfect developments up to the complex
arrangements and nice adaptations of the advanced tribes. But the
progress is not regular, nor are the intervals of constant length. The
line is often broken and doubled, and, in fact, the individuals are far
more naturally arranged in a number of parallel lines, beginning
successively at a somewhat lower point, than in a single series. Man, of
course, is placed at the head of the animal tribes; but the interval
which separates him from the chimpanzee cannot easily be cleared at one
bound. He forms but one genus, and that genus is the only one of its
order. But even if the line of gradation were single and perfect, the
fact would be of no service to the hypothesis we are now considering;
for the interval between two species most nearly allied to each other
seems to be quite as impassable as the broadest gulf of separation.

The point chiefly relied upon to show the credibility of this doctrine
is the fact, according to our author, that the higher animals pass
through a series of changes resembling the permanent forms of the lower
tribes. The first form of man himself "is that which is permanent in the
animalcule"; and thence he comes to resemble successively a fish, a
reptile, a bird, and the lower mammifers, before he attains his specific
maturity. It is held, then, that a premature birth from an animal of a
higher kind might have instituted a new race of a lower type; and that a
birth unusually delayed, permitting an embryo to be still farther
advanced in the line of organization, might have created a new species
of a higher order than the parent. Here, every thing depends on the
_absolute identity_ of the germs of all animals, in the lower stages of
their growth. General resemblances and analogies are of no weight
whatever; the essential internal organization of the ova of different
species must be the same; otherwise, however ripened into a mature
being, whether the birth be advanced or postponed, the individual must
still belong to its parents' species, of which it possesses the
distinctive peculiarity. Now, this point of _the identity of germs is a
mere assumption_; not only is it destitute of proof,--the whole evidence
is against it. There is a degree of outward resemblance, but there is no
sameness. When we trace the origin of life back to the remotest point to
which our powers of observat