We need the tonic of
wildness
to wade sometimes in marshes where the bittern and the meadow-hen
lurk,
and hear the booming of the snipe; to smell the whispering sedge
where only some wilder and more solitary fowl builds her nest, and
the mink crawls with its belly close to the ground. At the same time
that we are earnest to explore and learn all things, we require that
all things be mysterious and unexplorable, that land and sea be
infinitely wild, unsurveyed and unfathomed by us because
unfathomable. We can never have enough of nature. We must be
refreshed by the sight of inexhaustible vigor, vast and titanic
features, the sea-coast with its wrecks, the wilderness with its
living and its decaying trees, the thunder cloud, and the rain which
lasts three weeks and produces freshets. We need to witness our own
limits transgressed, and some life pasturing freely where we never
wander-Thoreau