lected to form it have
been other than gradual and almost imperceptible. Suppose that it has {138}
taken five hundred years to form the greyhound out of his wolf-like
ancestor. This is a mere guess, but it gives the order of the magnitude."
Now, if so, "how long would it take to obtain an elephant from a protozoon,
or even from a tadpole-like fish? Ought it not to take much more than a
million times as long?"[139]

Mr. Darwin[140] would compare with the natural origin of a species
"unconscious selection, that is, the preservation of the most useful or
beautiful animals, with no intention of modifying the breed." He adds: "But
by this process of unconscious selection, various breeds have been sensibly
changed in the course of two or three centuries."

"Sensibly changed!" but not formed into "new species." Mr. Darwin, of
course, could not mean that species _generally_ change so rapidly, which
would be strangely at variance with the abundant evidence we have of the
stability of animal forms as represented on Egyptian monuments and as shown
by recent deposits. Indeed, he goes on to say,--"Species, however, probably
change much more slowly, and within the same country only a few change at
the same time. This slowness follows from all the inhabitants of the same
country being already so well adapted to each other, that places in the
polity of nature do not occur until after long intervals, when changes of
some kind in the physical conditions, or through immigration, have
occurred, and individual differences and variations of the right nature, by
which some of the inhabitants might be better fitted to their new places
under altered circumstances, might not at once occur." This is true, and
not only will these changes occur at distant intervals, but it must be
borne in mind that in tracing back an animal to a remote ancestry, we pass
through modifications of such rapidly increasing number and importance that
a geometrical progression can alone indicate the increase of periods {139}
which such profound alterations would require for their evolution through
"Natural Selection" only.

Thus let us take for an example the proboscis monkey of Borneo
(_Semnopithecus nasalis_). According to Mr. Darwin's own opinion, this form
might have been "sensibly changed" in the course of two or three centuries.
According to this, to evolve it as a true and perfect species one thousand
years would be a very moderate period. Let ten thousand years