What are school blue devils?

Famous quotes containing the words devils, school and/or blue:

    Right as the humour of melancholy
    Causeth full many a man in sleep to cry
    For fear of blacke bears, or bulles black,
    Or elles blacke devils will them take.
    Geoffrey Chaucer (1340?–1400)

    One non-revolutionary weekend is infinitely more bloody than a month of permanent revolution.
    Graffiti, School of Oriental Languages, London (1968)

    That air would disappear from the whole earth in time, perhaps; but long after his day. He did not know just when it had become so necessary to him, but he had come back to die in exile for the sake of it. Something soft and wild and free, something that whispered to the ear on the pillow, lightened the heart, softly, softly picked the lock, slid the bolts, and released the prisoned spirit of man into the wind, into the blue and gold, into the morning, into the morning!
    Willa Cather (1873–1947)