Analysis of Droop'st thou and fail'st? but these have never tired

Droop'st thou and fail'st? but these have never tired;
winds of the region, free, they shine and sing,
unurged, unguerdon'd: hast thou then desired
to be with them and trail'st a useless wing?
Self-pity hath thee in her clinging damp,
and makes a siren-music of thy woes
to lure thy feet into that reptile-swamp
where rancour's muddy stream, festering, throes.
Cunning is her condolence with the snarl
of canker'd memory or the soft tear
for vanisht sweetness: come, an honest parle,
air for thy ailment! make these wrongs appear.
Ay, this hath spat at thee, and that hath flung
his native mud, and that with bilious guile
most plausible — what! hast thou loved and sung
as was in thee, and need'st do else than smile?
(Heed not that subtle demon that would prompt
to measure thee by them; so humbled yet
thou art not, nor so beggar'd thine accompt:
what thou art, that thou hast, and know'st thy debt.)
And in thy house of love the venom'd dart
was thrust within thy side — Even so! must then
the gather'd ripeness of thy mind and heart
be turn'd to flies? that is no way for men.
Who said, and rid himself of usual awe,
I prize not man, save as his metal rings
of god or hero? Hast thou made a law,
live by thy law: 'tis carrion hath no wings.