e see that
wherever civilization enters, and even where its first influences are
felt, the olden societies of nature are disturbed or broken up. All the
nobler members of these associations, the greater mammals, many of the
larger birds, and a host of the lesser forms, are expelled or destroyed.
In the condition of organic life when the supremely predatory creature
man rose to domination, the species were grouped in those vast
organizations which were of old termed faunae and florae, but which are
now better known as biological fields or provinces. In each of these
hosts the several species were, as regards their external life, so
balanced with their neighbors that the assemblage from the point of view
of these relations might well be compared with the polities or states of
man's construction. Such an organic society represents the result of a
series of trials and balances which began to be made in the immeasurably
remote past and have been continued through the geologic ages, each age
adding something to the accord. The plants give and take from the
animals; the insects are equated with the birds, and each species in
every group has set up an accord with its rivals. From time to time the
host has by the changes of sea and land been compelled to migrate,
moving this way and that to find its fit station. In these movements
species are rapidly extinguished, much as the weaker soldiers of an army
perish in forced marches. Into their places new forms hasten to take
their place, so that every position of advantage is filled. At a less
rapid rate, but perpetually, even without the change of abode, which it
is often by climatic changes compelled to make, the organic host is
slowly changing in character; old kinds give way in the endless contest
to new varieties which have managed to establish a better relation to
the environment. Still the legions press on towards the great
accomplishment of a higher and nobler life.

No one, however well he may conceive the nature and history of the
organic hosts of the earth, can hope to convey to the general reader
an adequate sense of their majesty or the wonderful part they have
played in the history of the life which has culminated in mankind. The
largest words are freighted with too little meaning, and even the
metaphors drawn from human associations fail to convey a sufficient
picture of these enduring organizations which have enabled living
beings to meet the difficulties of their lon