f
perpetual motion, or self-supplying power. They are not turned, they
turn; they are not repaired, they repair. The nature of living things
cannot be interpreted by the laws of mechanical and chemical things,
though mechanics and chemistry play the visible, tangible part in them.
If we must discard the notion of a vital force, we may, as Professor
Hartog suggests, make use of the term "vital behavior."

Of course man tries everything by himself and his own standards. He
knows no intelligence but his own, no prudence, no love, no mercy, no
justice, no economy, but his own, no god but such a one as fits his
conception.

In view of all these things, how man got here is a problem. Why the
slender thread of his line of descent was not broken in the warrings and
upheavals of the terrible geologic ages, what power or agent took a hand
in furthering his development, is beyond the reach of our biologic
science.

Man's is the only intelligence, as we understand the word, in the
universe, and his intelligence demands something akin to intelligence in
the nature from which he sprang.

VII

LIFE AND MIND

I

There are three kinds of change in the world in which we live--physical
and mechanical change which goes on in time and place among the tangible
bodies about us, chemical change which goes on in the world of hidden
molecules and atoms of which bodies are composed, and vital change which
involves the two former, but which also involves the mysterious
principle or activity which we call life. Life comes and goes, but the
physical and chemical orders remain. The vegetable and animal kingdoms
wax and wane, or disappear entirely, but the physico-chemical forces are
as indestructible as matter itself. This fugitive and evanescent
character of life, the way it uses and triumphs over the material
forces, setting up new chemical activities in matter, sweeping over the
land-areas of the earth like a conflagration, lifting the inorganic
elements up into myriads of changing and beautiful forms, instituting a
vast number of new chemical processes and compounds, defying the
laboratory to reproduce it or kindle its least spark--a flame that
cannot exist without carbon and oxygen, but of which carbon and oxygen
do not hold the secret, a fire reversed, building up instead of pulling
down, in the vegetable with power to absorb and transmute the inorganic
elements into leaves and fruit and tissue; in the animal with power to
ch