From Duncan's first letter to Denise Levertov in June 1953, "An A Muse Ment":

            song of the languagers
What are the signs of life? the breath, pulse,
  the constant
sloughing off of old disguises in
  creasing, increasing—
Notes— to hesitate, retract:
  step by step— to be idiot-awkward
  with it— to take care
by the throat & throttle it—
  bottle that genius
for mere magic or intoxic
  vacation.
it is sober he stumbles
  on truth? Hell, no—
this he sober gnaws
the inconsequential
  eternity of his skull.

His appetite is not experimental.