e by no means the least. I long ago had very direct proof of
this statement. In some of my English sketches, following a visit to
that island in 1882, I had, rather by implication than by positive
statement, inclined to the opinion that the European forms of animal
life were, as a rule, larger and more hardy and prolific than the
corresponding forms in this country. Roosevelt could not let this
statement or suggestion go unchallenged, and the letter which I
received from him in 1892, touching these things, is of double
interest at this time, as showing one phase of his radical
Americanism, while it exhibits him as a thoroughgoing naturalist.
I am sure my readers will welcome the gist of this letter. After
some preliminary remarks he says:--

"The point of which I am speaking is where you say that the Old World
forms of animal life are coarser, stronger, fiercer, and more fertile
than those of the New World." (My statement was not quite so sweeping
as this.) "Now I don't think that this is so; at least, comparing the
forms which are typical of North America and of northern Asia and
Europe, which together form but one province of animal life.

"Many animals and birds which increase very fast in new countries, and
which are commonly spoken of as European in their origin, are really
as alien to Europe as to their new homes. Thus the rabbit, rat, and
mouse are just as truly interlopers in England as in the United States
and Australia, having moved thither apparently within historic times,
the rabbit from North Africa, the others from southern Asia; and one
could no more generalize upon the comparative weakness of the American
fauna from these cases of intruders than one could generalize from
them upon the comparative weakness of the British, German, and French
wild animals. Our wood mouse or deer mouse retreats before the
ordinary house mouse in exactly the same way that the European wood
mouse does, and not a whit more. Our big wood rat stands in the same
relation to the house rat. Casting aside these cases, it seems to me,
looking at the mammals, that it would be quite impossible to
generalize as to whether those of the Old or the New World are more
fecund, are the fiercest, the hardiest, or the strongest. A great many
cases could be cited on both sides. Our moose and caribou are, in
certain of their varieties, rather larger than the Old World forms of
the same species. If there is any difference between the beavers of
t