I never, of course, could have guessed at; and imagine my still greater
satisfaction at your expressing yourself as an unbeliever in the eternal
immutability of species. Your final remarks on my work are too generous,
but have given me not a little pleasure. As for criticisms, I have only
small ones. When you speak of "moderate range of variation" I cannot but
think that you ought to remind your readers (though I daresay previously
done) what the amount is, including the case of the American bog-mammoth.
You speak of these animals as having been exposed to a vast range of
climatal changes from before to after the Glacial period. I should have
thought, from analogy of sea-shells, that by migration (or local extinction
when migration not possible) these animals might and would have kept under
nearly the same climate.

A rather more important consideration, as it seems to me, is that the whole
proboscidean group may, I presume, be looked at as verging towards
extinction: anyhow, the extinction has been complete as far as Europe and
America are concerned. Numerous considerations and facts have led me in
the "Origin" to conclude that it is the flourishing or dominant members of
each order which generally give rise to new races, sub-species, and
species; and under this point of view I am not at all surprised at the
constancy of your species. This leads me to remark that the sentence at
the bottom of page [80] is not applicable to my views (143/2. See Falconer
at the bottom of page 80: it is the old difficulty--how can variability
co-exist with persistence of type? In our copy of the letter the passage
is given as occurring on page 60, a slip of the pen for page 80.), though
quite applicable to those who attribute modification to the direct action
of the conditions of life. An elephant might be more individually variable
than any known quadruped (from the effects of the conditions of life or
other innate unknown causes), but if these variations did not aid the
animal in better resisting all hostile influences, and therefore making it