Notes on the current edition
Poetics
1.
i. e. one imitative work. Thus one picture represents, or should represent, but one thing; a single object, or a single action, &c. So, every Poem, (the Orlando Furioso as much as the Iliad,) is one imitation—one imitative work, and should imitate one action, in Aristotle's sense of unity, like the Poems of Homer; not a number of actions unconnected with each other, or connected merely by their common relation to one person, as in the Theseids, &c. or to one time, as in the Poem of Ariosto; or, by their resemblance merely, as in the Metamorphoses of Ovid.
2.
"The painter will not enquire what things may be admitted without much censure. He will not think it enough to shew that they may be there, he will shew that they must be there; that their absence would render his picture maimed and defective. They should make a part of that whole which would be imperfect without them." Sir J. Reynolds, Disc. on Painting, p. 106.