Now diction[60] [in its sentence-movement] is connected either loosely and only by conjunctions, as the preludes in the dithyrambs, or compactly, as the antistrophes of the old poets. The former movement is the old one, as in Herodotus; for, though once universal, it is now exceptional. By calling it loose I mean that it has no end in itself except as its subject-matter runs out. It is unsatisfying to the ear by its indefiniteness, since we all wish to glimpse the end. That [natural desire] is why [runners] lose wind and heart only at the goal. They do not give out before because they are looking ahead to the finish. The loose movement, then, of diction is this; the compact, on the other hand, is the one by periods [or definite units]. By _period_ I mean a diction having a beginning and an end in itself and a length to be grasped as a whole. Such sentence-movement is both satisfying to the ear and easily followed by the mind;[61] _satisfying_ as being the opposite of endless and as giving the hearer the sense of always having hold of something, because something has always been ended by itself, whereas the unsatisfying is neither to see ahead nor to get through; _easily followed_, as being easily held in mind, and that because periodic diction has number, which is the chief aid to memory. That is why verses are more easily remembered than loose prose, because verse has number to measure it. The period should also be completed with the sense, not broken off.... A period[62] is either in members or simple. Composed in members, it is such a diction as makes a rounded whole and yet is distinct in its parts, and such as the breath will carry easily, not by [arbitrary] division, but as a whole. A member is one of its parts; and by simple period I mean a period of one member. Both members and periods should be neither curt[63] nor long. For short [members] often make the hearer stumble, since while he is still surging ahead, if he is pulled up by the stopping of the measure that he carries in his head as a guide, he must stumble as in a collision. Long [members] on the other hand make the hearer feel himself left behind, as by walking companions making the turn beyond the usual stretch.... Over-use of short members, since it precludes the periodic form, drags the hearer headlong.