At Twilight (in Short Story Collection Vol. 036 )

A breeze from the May world without blew through the class-room, and as
it lifted his papers he had a curious sense of freshness and mustiness
meeting. He looked at the group of students before him, half smiling at
the way the breath of spring was teasing the hair of the girls sitting
by the window. Anna Lawrence was trying to pin hers back again, but May
would have none of such decorum, and only waited long enough for her
to finish her work before joyously undoing it. She caught the laughing,
admiring eyes of a boy sitting across from her and sought to conceal her
pleasure in her unmanageable wealth of hair by a wry little face, and
then the eyes of both strayed out to the trees that had scented
that breeze for them, looking with frank longing at the campus which
stretched before them in all its May glory that sunny afternoon. He
remembered having met this boy and girl strolling in the twilight the
evening before, and as a buoyant breeze that instant swept his own face
he had a sudden, irrelevant consciousness of being seventy-three years
old.

Other eyes were straying to the trees and birds and lilacs of that world
from which the class-room was for the hour shutting them out. He was
used to it--that straying of young eyes in the spring. For more than
forty years he had sat at that desk and talked to young men and women
about philosophy, and in those forty years there had always been
straying eyes in May. The children of some of those boys and girls had
in time come to him, and now there were other children who, before
many years went by, might be sitting upon those benches, listening to
lectures upon what men had thought about life, while their eyes strayed
out where life called. So it went on--May, perhaps, the philosopher
triumphant.