great alteration. The
Egyptian of the old tombs is much like the Egyptian of the same rank
to-day. The African of the tombs has the African features of to-day.
Under such circumstances it is hard to prove that there is a steady
and undoubted advance. For the most part the balance of the animal
world is fairly even, and any species does not ordinarily change
rapidly enough or migrate widely enough to show us its new features.
It is difficult to see the struggle which we are so sure is going on.
The life of animals is so hidden in many of its details that their
joys and sorrows, if such we may call them, scarcely fall under our
observation. Now and then an opportunity comes to see the process of
adaptation work itself out. The struggle for existence begins anew and
is carried on with special vigor, with victory, temporary or
permanent, to one of the participants in the struggle.

The opportunity to observe such a change is presented in the United
States by the introduction of the so-called English sparrow. This
little creature, received at first with such joy, soon became the
object of an almost bitter hatred on the part of very many people.
This is really due to the fact that this bird is one of nature's
darlings and thoroughly succeeds where it has an even chance.

The number of birds of any particular species which a region will
support seems to be fairly definite. If a species is especially
protected until it becomes unusually abundant, the removal of the
protection commonly brings it down promptly to its original numbers.
On the other hand, an accident of severe character or a special
persecution may much diminish the number of the species, and still it
will, within a comparatively few years, return to its previous
abundance.

The inhabitants of Florida who own orange groves will never forget the
winter of '94-5. A bitter cold wave swept along the coast and killed
such large numbers of orange trees as almost to cut Florida out of the
orange market and to open the gate to California, who was eagerly
offering her fruit. This same frost caught the migrating blue birds
and killed them by the thousands. When spring came bird-lovers
throughout the eastern United States found an astonishing scarcity of
these favorites. It was feared that with numbers so small they could
not possibly compete with their enemies and with whatever untoward
circumstances should be their lot. But there is room in this
environment for a defin