letter; and another Discovery was required to reveal him to Iphigenia. Two parts of the Plot, then, Peripety and Discovery, are on matters of this sort. A third part is Suffering; which we may define as an action of a destructive or painful nature, such as murders on the stage, tortures, woundings, and the like. The other two have been already explained. 12 The parts of Tragedy to be treated as formative elements in the whole were mentioned in a previous Chapter. From the point of view, however, of its quantity, i.e. the separate sections into which it is divided, a tragedy has the following parts: Prologue, Episode, Exode, and a choral portion, distinguished into Parode and Stasimon; these two are common to all tragedies, whereas songs from the stage and Commoe are only found in some. The Prologue is all that precedes the Parode of the chorus; an Episode all that comes in between two whole choral songs; the Exode all that follows after the last choral song. In the choral portion the Parode is the whole first statement of the chorus; a Stasimon, a song of the chorus without anapaests or trochees; a Commas, a lamentation sung by chorus and actor in concert. The parts of Tragedy to be used as formative elements in the whole we have already mentioned; the above are its parts from the point of view of its quantity, or the separate sections into which it is divided. 13 The next points after what we have said above will be these: (1) What is the poet to aim at, and what is he to avoid, in constructing his Plots? and (2) What are the conditions on which the tragic effect depends? We assume that, for the finest form of Tragedy, the Plot must be not simple but complex; and further, that it must imitate actions arousing pity and fear, since that is the distinctive function of this kind of imitation. It follows, therefore, that there are three forms of Plot to be avoided. (1) A good man must not be seen passing from happiness to misery, or (2) a bad man from misery to happiness.