When an Athenian Esop saw, Playing with school-boys once at taw, The man with laughter shook his sides; Esop the laughter thus derides: "Of this slack bow before you laid, The meaning, sprightly sir," he said, "Explain!" (A crowd had gather'd round.) Surpris'd, the man no answer found: He puzzled long, but all his wit Could on no explanation hit. The laugh on Esop's side; says he, "Why you this bow unbended see, It is because it needs must break, If always bent; so we must take Due relaxation, that the mind Its vigor may when wanted find."