The poem is written in iambic trimeter. An iambic poetic foot consists of an unstressed syllable followed by a stressed syllable. A trimeter is a line that comprises three feet.

The poem’s rhyme scheme is a b c b d e f e; that is, in each stanza, line 2 rhymes with line 4, and line 6 rhymes with line 8. The other four lines are unrhymed and have an extra syllable at the end of the line. This extra unstressed syllable is known as a feminine ending. The other line endings, with stressed syllables, are known as masculine endings. The rhymes are perfect rhymes because both consonant and vowel sounds rhyme (“breed” and “need,” for example, in Lines 2 and 4).

The first line of the poem is repeated in the first lines of all the subsequent stanzas, which emphasizes the poem’s main theme. This device is like a refrain, which is often used in songs as well as poetry, although a refrain is usually placed at the end of a verse. The repetition is most effective, as are other literary devices of the poem, when the poem is read aloud.