History is a fragment of biology: the life of man is a portion of the vicissitudes of organisms on land and sea. Sometimes, wandering alone in the woods on a summer day, we hear or see the movement of a hundred species of flying, leaping, creeping, crawling, burrowing things. The startled animals scurry away at our coming; the birds scatter; the fish disperse in the brook. Suddenly we perceive to what a perilous minority we belong on this impartial planet, and for a moment we feel, as these varied denizens clearly do, that we are passing interlopers in their natural habitat.
