come, the more numerous are
the proofs that all is more or less shaded (_nuance_), that the
remarkable differences become obliterated, and that the more often
nature leaves it at our disposal to establish distinctions only
minute, and in some degree trivial peculiarities.

"But some genera among animals and plants are of such an extent,
from the number of species they contain, that the study and the
determination of these species are now almost impossible. The
species of these genera, arranged in series and placed together
according to their natural relations, present, with those allied to
them, differences so slight that they shade into each other; and
because these species are in some degree confounded with one another
they leave almost no means of determining, by expression in words,
the small differences which distinguish them.

"There are also those who have been for a long time, and strongly,
occupied with the determination of the species, and who have
consulted rich collections, who can understand up to what point
species, among living bodies, merge one into another (_fondent les
unes dans les autres_), and who have been able to convince
themselves, in the regions (_parties_) where we see isolated
species, that this is only because there are wanting other species
which are more nearly related, and which we have not yet collected.

"I do not mean to say by this that the existing animals form a very
simple series, one everywhere equally graduated; but I say that they
form a branching series, irregularly graduated, and which has no
discontinuity in its parts, or which at best has not always had, if
it is true that it is to be found anywhere (_s'il est vrai qu'il
s'en trouve quelque part_). It results from this that the species
which terminates each branch of the general series holds a place at
least on one side apart from the other allied species which
intergrade with them. Behold this state of things, so well known,
which I am now compelled to demonstrate.

"I have no need (_besoin_) of any hypothesis or any supposition for
this: I call to witness all observing naturalists.

"Not only many genera, but entire orders, and some classes even,
already present us with portions almost complete of the state of
things which I have just indicated.

"However, when in this case we have arranged the species in series,
and they are all well placed