slightest cause for his terror. But--I heard!
Sh-sh-sh--I was aware of a light step in the needles under the tree he
had left. Straining my eyes to watch the ground, surely, surely, in a
line passing close to my couch, the needles and thin grass were
pressed down, as if by a weight applied at even distances! I had
remained motionless as a figure of stone, but when a tuft of hepatica,
blooming late where the shade was deepest, fell crushed near my hand,
I reached out. As luck would have it I was too conscious, too much
ashamed at my own folly to act decisively. I did not grasp, I reached
out--and touched a living thing.

On such occasions there comes at first the exuberance of joy; then
doubt. I had long debated the possibility of invisibles. As far back
as I can remember, elfin tales produced an awful wonderment upon my
imagination. On long May nights have I not often stolen from the house
to watch for elves? A moon after a rain was to my thinking the best
for such mysterious beings, when everything was hazy with an
imperceptible mist, when the dogwoods had flooded the landscape with
sheets of reflected white, and somebody was drawing one veil after
another slowly past a golden shield in the sky. On such nights, more
than once, a boy might have been seen creeping on tiptoe through the
open woods, over the great clearing, to the hill-top, where, if
anywhere, brownies must play. But none did he espy, nor did the
chance-flung cap ever fall upon his eager, outstretched hands. And if
in later years the subject still fascinated me, it made me feel what
the grown man realizes always more clearly, that fables and fairy
tales rest on a solid groundwork of fact. Why, when so many other
legends have been verified, should this universal tradition of
vanishers and invisibles prove entirely false?

It occurs to one very soon that animal life does exist of so
transparent a texture that to all intents and purposes it is
invisible. The spawn of frogs, the larvae of certain fresh-water
insects, many marine animals, are of so clear a tissue that they are
seen with difficulty. In the tropics a particular inhabitant of smooth
seas is as invisible as a piece of glass, and can be detected only in
the love season by the color which then mingles in its eyes. On
reflection a thousand instances arise of assimilation of animal life
to their surroundings, of mimicry of nature with a view to safety.
Why, then, by survival of the most transparent,