say, become perfected or degraded,
through great changes in the distribution of land and ocean, through the
cultivation or neglect of the country which they inhabit, through the
long-continued effects of climatic changes, so that they are no longer
the same animals that they once were? Yet of all living beings after
man, the quadrupeds are the ones whose nature is most fixed and form
most constant: birds and fishes vary much more easily; insects still
more again than these, and if we descend to plants, which certainly
cannot be excluded from animated nature, we shall be surprised at the
readiness with which species are seen to vary, and at the ease with
which they change their forms and adopt new natures.

"It is probable then that all the animals of the new world are derived
from congeners in the old, without any deviation from the ordinary
course of nature. We may believe that having become separated in the
lapse of ages, by vast oceans and countries which they could not
traverse, they have gradually been affected by, and derived impressions
from, a climate which has itself been modified so as to become a new one
through the operation of those same causes which dissociated the
individuals of the old and new world from one another; thus in the
course of time they have grown smaller and changed their characters.
This, however, should not prevent our classifying them as different
species now, for the difference is no less real whether it is caused by
time, climate and soil, or whether it dates from the creation. _Nature I
maintain is in a state of continual flux and movement. It is enough for
man if he can grasp her as she is in his own time, and throw but a
glance or two upon the past and future, so as to try and perceive what
she may have been in former times and what one day she may attain
to._"[104]

_The Buffalo--Animals under Domestication._

"The bison and the aurochs," says Buffon, "differ only in unessential
characteristics, and are, by consequence, of the same species as our
domestic cattle, so that I believe all the pretended species of the ox,
whether ancient or modern, may be reduced to three--the bull, the
buffalo, and the bubalus.

"The case of animals under domestication is in many respects different
from that of wild ones; they vary much more in disposition, size and
shape, especially as regards the exterior parts of their bodies: the
effects of climate, so powerful throughout nature, act with far