Under the influence of the life impulse, the old routine of matter--from
compound to compound, from solid to fluid, from fluid to gaseous, from
rock to soil, the cycle always ending where it began--is broken into,
and cycles of a new order are instituted. From the stable equilibrium
which dead matter is always seeking, the same matter in the vital
circuit is always seeking the state of unstable equilibrium, or rather
is forever passing between the two, and evolving the myriad forms of
life in the passage. It is hard to think of the process as the work of
the physical and chemical forces of inorganic nature, without
supplementing them with a new and different force.

The forces of life are constructive forces, and they are operative in a
world of destructive or disintegrating forces which oppose them and
which they overcome. The physical and chemical forces of dead matter are
at war with the forces of life, till life overcomes and uses them.

The mechanical forces go on repeating or dividing through the same
cycles forever and ever, seeking a stable condition, but the vital force
is inventive and creative and constantly breaks the repose that organic
nature seeks to impose upon it.

External forces may modify a body, but they cannot develop it unless
there is something in the body waiting to be developed, craving
development, as it were. The warmth and moisture in the soil act alike
upon the grains of sand and upon the seed-germs; the germ changes into
something else, the sand does not. These agents liberate a force in the
germ that is not in the grain of sand. The warmth of the brooding fowl
does not spend itself upon mere passive, inert matter (unless there is a
china egg in the nest), but upon matter straining upon its leash, and in
a state of expectancy. We do not know how the activity of the molecules
of the egg differs from the activity of the molecules of the pebble,
under the influence of warmth, but we know there must be a difference
between the interior movements of organized and unorganized matter.

Life lifts inert matter up into a thousand varied and beautiful forms
and holds it there for a season,--holds it against gravity and chemical
affinity, though you may say, if you please, not without their aid,--and
then in due course lets go of it, or abandons it, and lets it fall back
into the great sea of the inorganic. Its constant tendency is to fall
back; indeed, in animal life it does fall back every moment