Medium Quotes in Poetics
Epic poetry and the composition of tragedy, as well as comedy and the arts of dithyrambic poetry and (for the most part) of music for pipe or lyre, are all (taken together) imitations. They can be differentiated from each other in three respects: in respect of their different media of imitation, or different objects, or a different mode (i.e. a different manner).
So tragedy as a whole necessarily has six component parts, which determine the tragedy’s quality. The medium of imitation comprises two parts, the mode one, and object three; and there is nothing apart from these.