"Dream" makes a giddy sound, not strong (1)
This first mention of dreams isn't exactly a ringing endorsement. Things that aren't strong are probably weak. A weak dream doesn't likely stand much of a chance of coming true.
But could a dream send up through onion fumesIts white and violet, fight with fried potatoes And yesterday's garbage ripening in the hall, (4–6)
Looks like we're getting a sense of what these dreams are up against—tough stuff, the grind and stink of everyday life. Brooks begins to pose the question at the heart of the poem: Will a "giddy," "not strong" dream be able to rise above it all?
Flutter, or sing an aria down these rooms (7)
This line echoes the question of lines 4–6. The speaker seems to think it unlikely that a dream could create its beautiful music in a place of such racket. It would seem out of place, like someone dressed in a ball gown to wash the bathroom floor.