The dog never actually appears in the poem. Only the title says "Old dog"; after that, the animal survives in a single verb, "bark," and the reader supplies the rest. That economy runs through the whole piece. Six short lines, no capitals and no punctuation still hold a workplace, old age, a stretch of open country and a creeping darkness. The central idea seems to be that age does not tame restlessness. The speaker is stuck in a job he resents, relieved only briefly by the outdoors, and threatened by something larger than irritation.
The opening couplet is a flat self-diagnosis: "bitter and old." There is no "I am," as if the speaker were reading a label on himself. "Bitter" works on two levels, a sour taste and a sour temper, and its hard b links it to "bark," which arrives a line later. The sound ties the mood to the noise. Then comes "how I still bark and bark," where "how" sits between exclamation and embarrassment, like someone overhearing himself complain. "Still" is the key word. It says that decades have not cured the habit, and the repeated "bark and bark" enacts the compulsion, since a dog barks at things it cannot change. The title also nudges us toward the proverb about old dogs and new tricks. This old dog has not learned the trick of keeping quiet.
The second couplet changes the setting and gives the poem its one moment of relief. "Open fields get me / out of my jealous office." Grammatically, the fields do the work and the speaker is carried along, like a dog let off the lead. "Jealous" is the most interesting word here. Jealousy belongs to people, not rooms, so the adjective is borrowed from a human feeling and pinned on a building. It can be read two ways. The office may be possessive, guarding his hours as a jealous owner guards a pet. Or the speaker may be jealous of everyone who is not shut inside. Either way, the office starts to look like a kennel. The sounds quietly set the two worlds side by side: "open" and "office" begin with the same vowel, and "fields" shares its f with "office," so the places are almost rhymed even as they pull in opposite directions.
The last couplet is the strangest. "A night at noon calling" is a paradox, darkness arriving at the brightest hour. The poem does not say whether this is weather, mood, or something nearer to mortality. The grammar is deliberately open too. Is the night calling, or is it calling someone? The missing object lets us hear a summons, a howl, even a vocation. The repeated n of "night," "noon" and "calling" gives the line a low hum. Then the final line, "eating me up," turns the idiom for being consumed by worry or jealousy into something almost literal. It echoes "jealous" from the line above, and it reverses the animal logic of the poem. The barking dog becomes the thing that is eaten.
Rhyme is absent, but the rhythm matters. The lines run roughly four and six syllables, then five and seven, then six and four. The poem lengthens as it gets out into the fields, then collapses into its shortest line, "eating me up." With no full stop, the ending feels unfinished, as though the devouring were still going on. The lack of punctuation also lets the poem be read in one breath, which suits a speaker who cannot stop barking.
What makes the poem worth reading is how much it leaves to the reader. A title can carry a whole metaphor, and a loosely built sentence can hold several meanings at once. It also avoids easy sentimentality about ageing. The speaker is bitter, a little ridiculous, and aware of it, and the fields offer relief but not a cure. The bark is a nuisance, but it is also proof that something in him is still alive and answering back, and the last line suggests that something is being worn down.