He asks the "wild bird," probably the nightingale, whose liquid song
brings a sense of Eden back again, to define the feelings of the heart,
its emotions and passions. In the "budded quicks" of Spring the bird is
happy; in the "darkening leaf," amid the shadowing foliage, though its
happiness be gone, its grieving heart can still cherish "a secret joy."
The notes of the nightingale are supposed to be both sorrowful and joyous.
Even so, the Poet cannot wholly govern his own muse; for, when he would
sing of woe,
"The glory of the sum of things,"
the grandeur of life's experience, will sometimes rule the chords.