In Chapter 7, I focus on the difference that functions in Don Juan as the type of all the other differences that the poem explores, the difference between what Byron has to say, and the form, ottava rima, in which he has to say it. The chapter asks what it might mean for a poem so frankly to confess how the poet is at the mercy of the demands of rhyme (‘This should be entre nous for Julia thought / In French, but then the rhyme would go for nought’) and of metre, as when he admits that he had added a word to a quotation from Horace simply because ‘prosody’ demanded it. Byron’s offences against rhyme and metre are carefully designed to prevent his readers from ever forgetting the difference between what he means to say and what the verse form he has chosen allows him to say.