Institutio Oratoria

But although partition is neither always necessary nor useful, it will, if judiciously employed, greatly

add to the lucidity and grace of our speech. For it not only makes our arguments clearer by isolating the points from the crowd in which they would otherwise be lost and placing them before the eyes of the judge, but relieves his attention by assigning a definite limit to certain parts of our speech, just as our fatigue upon a journey is relieved by reading the distances on the milestones which we pass.