erhaps be maintained, but that duration cannot be
looked upon as more than a moment in the limitless progress we are
considering, and it was in this view that Cuvier's doctrine proved to be
incapable of defence. [Sidenote: Imperfection of evidence in its
support.] What does it signify if our domestic animals show no
variations when compared with the corresponding images depicted on the
hieroglyphic monuments of Egypt, or with the descriptions left by
ancient authors? Evidence of that kind is valueless. Does the geologist
ask of the architect his opinion whether there have ever been upliftings
and down-sinkings of the earth? If he did, would not every structure in
Europe be brought forward as an evidence that nothing of the kind had
ever occurred? A leaning tower, or a church with inclining walls in
Italy, might pass for nothing; the Pyramids would testify that Egypt
itself had never undergone any disturbance--they remain solid on their
bases, undisturbed. But what is the weight of all this when placed in
opposition with the mass of evidence offered by inclined and fractured
strata? And yet such is precisely the proof offered in behalf of the
permanence of animals. The facts with which the zoologist deals, like
those on which the architect depends, are insufficient for the
purpose--they are wanting in extent of time. There have been movements
in the crust of the earth, though every building in the world may be
perpendicular; there have been transformations of organisms, though for
four thousand years there may have been no perceptible change.

[Sidenote: Control of organisms by physical conditions.] If ever there
had been a universal creation of all possible organic forms or
combinations, forthwith vast numbers of them must have disappeared,
every type being eliminated which was not in correspondence with the
external conditions or with the medium in which it was placed. If the
environment or the physical conditions underwent a variation, a
corresponding variation in the forms that could by possibility exist
must ensue, and, from a thorough study of those not eliminated, the
physical conditions might be ascertained; and conversely, from a
thorough knowledge of the physical conditions, the forms that could
escape elimination might be designated. The facts on which Cuvier rested
did not demonstrate what he supposed. His immobility of species was no
consequence of an innate or intrinsic resistance possessed by them, but
mer