power. Their life, if such a term can be used, is not the
property of themselves, but of the ocean to which they belong.

Influences which thus metaphorically give life to the sea, in reality
give life to the land. Under their genial operation a wave of verdure
spreads over the earth, and countless myriads of animated things attend
it, each like the eddies and ripples of the sea, expending its share of
the imparted force. The life of these accidental forms, through which
power is being transposed, belongs, not to itself, but to the universe
of which it is a part.

[Sidenote: Nature of animals.] Of the waves upon the ocean there may not
be two alike. The winds, the shores, their mutual interferences, a
hundred extraneous influences, mould them into their ephemeral shapes.
So those collections of matter of which animated things consist offer a
plastic substance to be modified. The number of individuals counts like
the ripples of the sea.

[Sidenote: They constitute a series.] As external circumstances change,
animated forms change with them, and thus arises a series of which the
members stand in a connected relation. The affiliated sequence of the
external circumstances is represented in the affiliated succession of
living types. From parts, or from things already existing, new parts and
new things emerge, the new not being added or juxtaposed to the old, but
evolved or developed from it. From the homogeneous or general, the
heterogeneous or special is brought forth. A new member, fashioned in
secrecy and apart, is never abruptly ingrafted on any living thing. New
animal types have never been suddenly located among old ones, but have
emerged from them by process of transmutation. As certainly as that
every living thing must die, so must it reach perfection by passing
through a succession of subordinate forms. An individual, or even a
species, is only a zoological phase in a passage to something beyond. An
instantaneous adult, like an immortal animal, is a physiological
impossibility.

[Sidenote: The doctrine of progressive improvement.] This bringing forth
of structure from structure, of function from function, incidentally
presents, upon the whole, an appearance of progressive improvement, and
for such it has been not unfrequently mistaken. Thus if the lowest
animals, which move by reflex action instantly but unconsciously, when
an impression is made upon them, be compared with the higher ones, whose
motions are exe