"Out of the Bag" begins with a strange declaration. Speaking in the first person plural, the speaker announces that "All of us came in Doctor Kerlin's bag." As the poem progresses, it will become clear that "us" refers to the speaker and his siblings. (Heaney himself was one of nine children!) And who is Doctor Kerlin? The poem is about to sketch him in great detail, but for now, the speaker seems more interested in the bag he'd "arrive with." Even as Doctor Kerlin vanishes into "the room" and prepares to do his work, the speaker stays fixated on the bag, keeping track of whether it's open or closed, empty or full.
Already, then, there's something mysterious about the bag. But there's also something ominous about the doctor. The speaker isn't allowed to follow him into "the room" (notice how the definite article "the" sets the room apart, signaling that there's something special about it). At the same time, Doctor Kerlin's arrival seems familiar or habitual: clearly, it's happened more than once before.
The speaker then watches, entranced, as Doctor Kerlin "reappear[s]" and scrubs his hands in the "scullery basin": a small, back-room sink for washing dishes and the like. The speaker again takes special note of Kerlin's bag, whose "lined insides," he observes, are "The colour of a spaniel's inside lug." (The term "lug," a UK colloquialism for ear, offers a clue as to the poem's setting.) In other words, the bag has a rich brown, shiny, soft interior lining. The sight of this luxurious fabric seems to have embedded itself in the speaker's memory.
The first two stanzas don't reveal too much about the speaker. The diction suggests an adult voice, but already, there are clues that this speaker is recalling events from early childhood. Consider line 4: "Those nosy, rosy, big, soft hands of his." The long string of adjectives, plus the internal rhyme of "nosy" and "rosy," is whimsical, enthusiastic, and childlike. This stanza also contains lots of sibilance, or soft /s/ and /z/ sounds:
Those nosy, rosy, big, soft hands of his
In the scullery basin, its lined insides
One could almost think of these sounds as the lisping of a young child. Even as the speaker revisits this childhood scene with the knowledge of an adult, he remains faithful to the impression Doctor Kerlin left so many years ago.