ly is the foundation of society. And family
and social life have been the school in which man has been compelled
to learn the moral lessons, the application of which has made him
what he is.

You must all, I think, have noticed that the different systems of
organs succeed one another in a certain definite order; and that
each stage from the lowest to the highest is characterized by the
predominance of a certain function or group of functions. This
sequence of functions is not a deduction but a fact. Place side by
side all possible genealogical trees of the animal kingdom, whether
founded on comparative anatomy, embryology, palaeontology, or all
combined. They will all disclose this sequence of functions arranged
in the same order. Let me call your attention to the fact that this
order is not due to chance, but rests upon a physiological basis. We
might almost claim that if the evolution of man from the single cell
be granted, no other order of their occurrence is possible.

The protozoa are mostly, though not purely, nutritive and
reproductive. These functions are essential to the existence of the
species. Naturally in the early protozoan colonies, and in forms
like hydra, these functions predominated. But mere digestive tissue
is not enough for digestion. Muscles are needed to draw the food to
the mouth, to keep the digestive sack in contact with it, and for
other purposes. A little higher they are used to enable the animal
to go in search of its food. They are still, however, more or less
entirely subservient to digestion. But in the highest worms we are
beginning to see signs that muscles are predominating in the body;
and we feel that, while mutually helpful, the digestive system
exists for the muscles, and these latter are becoming the aim of
development. From worms upward there is a marked advance in physical
activity and strength. The muscles thicken and are arranged in
heavier bands. Skeleton and locomotive appendages and jaws follow in
insects and vertebrates. The direct battle of animal against animal,
and of strength opposed to strength or activity, becomes ever
sharper. The strongest and most active are selected and survive.

And yet this is not the whole truth. Some power of perception is
possessed by every animal. But until muscles had developed the
nervous system could be of but little practical value. Knowledge of
even a great emergency is of little use, if I can do nothing about
it. But when the mus