But follows light's guidance,—will famish, not feast?
In such various degree, fly and worm, ore and plant,
All know, none is witless: around each, a wall
Encloses the portion, or ample or scant,
Of Knowledge: beyond which one hair's breadth, for all
Lies blank—not so much as a blackness—a pall
Some sense unimagined must penetrate: plain
Is only old license to stand, walk or sit,
Move so far and so wide in the narrow domain
Allotted each nature for life's use: past it