A poem about a snowy afternoon with a child begins in a museum and stops to quote a dictionary. That detour is the key to the whole piece. The speaker learns the word "purlieu" from an exhibit title and looks it up. The entry gives him a cluster of meanings: a frequently visited place, an outlying district, "confines, bounds," "neighborhood, environs." Its medieval sense is land "severed from an English royal forest by perambulation," meaning land marked off by walking its edges. Everything after that is a perambulation. The speaker and his niece Eva walk a patch of ground that is half familiar and half wild, and the poem tries to work out who owns it, who sees it best, and what a walk through it leaves behind.
The opening shows how the poem is built. It starts in short, carefully broken lines, with Eva hoisted up "by the armpits / for a five-second look" at tiny landscapes. Then the dictionary entry arrives, and after that the poem relaxes into long paragraphs of prose. There is no rhyme and no steady meter. The rhythm comes from speech, especially the quick back-and-forth of the dialogue: "Are we ever going to find these deer?" "Probably not." The form copies the walk itself, beginning with a view framed on a wall and ending in open ground where nobody lifts anyone up to see.
The imagery of tracks carries most of the poem's thought. Eva discovers that "if you follow an animal's tracks, you can tell where it went," and the two become "detectives." But the speaker has to admit that tracks made before the night's fresh snow lead nowhere useful, so "animal tracks can't be trusted to take you where you want to go." This reads like a small joke, but it also hints at something larger about following any trail, including a child's attention, which keeps veering off to a new discovery. Eva's wish "to walk without leaving any footprints" adds to this. Her uncle's reply is a lesson in physics: "The only things that don't are the ones with wings."
That line pays off at the end. Sledding down the hill, Eva "goes airborne at each bump" and then examines "the places where the saucer left the ground." Her closing question, "Did you see me flying?", answers the wish for a trackless walk. Flight is the one place the child finds where she leaves no trace. The scene also reverses the opening. In the museum the adult lifts the child to see a world in miniature. On the hill the speaker is at the bottom "looking up" at "a small red figure" jumping with glee, so the child is now the one who is high up and seeing farther.
The adult's role is subtler than that of a guide. He has a quiet, protective discretion. He says nothing about the deer carcass ("which neither of us mentions") and hides his fear on the sled: "I would've been terrified at her age, but I don't tell her that." Death and fear both sit at the edges of this ground, and the two walkers silently agree to keep them there. Meanwhile Eva's perceptions are sharper than his. She notices that adults hold money "as if it were fragile," and she claims the snow tastes different from place to place. When he says adults lose their sense of taste, he is half teasing and half sincere. Her cotton-candy snow is funnier still: she has never tasted cotton candy, yet she still insists on the comparison. Imagination here works without any experience behind it.
The poem matters because it takes the fussy, scholarly word "purlieu" and shows what it feels like in practice. A purlieu is a place you keep returning to, and its edges are made by walking them. For Eva the woods are a place to live in, with blankets and tea and "a kind of a house. Well, not with walls." The poem never states its idea outright. It leaves it in the image of a trail of footprints, a few of them stopping where the ground ends and the flying begins.