The theatrical illusion is still further heightened, or, to be quite correct, is still more entirely forgotten, when some of the characters in a play themselves perform a play, as in _Hamlet_ or _A Midsummer Night's Dream_. It seems extraordinary or impossible that the spectators of this second play should also be acting. The illusion here is artificially strengthened, and yet at the same time weakened, by attention being drawn to it. It is plain that this play with illusions had an immense attraction for Tieck; it was inevitable that it should have. Since it is illusion which makes art serious reality to the spectator, it is by the destroying of the illusion that he is made to feel strongly that art is free, fanciful play. So Tieck mocks ironically at things which are usually ignored in order not to disturb the illusion. In _Puss in Boots_ the King says to Prince Nathaniel: "But do tell me; how is it that you who live so far away can speak our language so fluently?" Nathaniel: "Hush!" The King: "What?" Nathaniel: "Hush, hush! For any sake be quiet, or the audience too will be finding out how unnatural it is." And, sure enough, one of the spectators presently remarks: "Why in the world can't the prince talk a foreign language and have it translated by his interpreter? What utter nonsense it all is!" This last speech is of course sarcasm, aimed at that demand for realism in art of which Iffland and Kotzebue were advocates. We have one expression of the demand in question in the French misconception of the Aristotelian doctrine of the unity of time and place. Writing on this subject, Schlegel, following Lessing's example, remarked that, after one had taken the great plunge and agreed to regard the stage as the world, it was surely easy to take the lesser one and sometimes permit the said stage to represent different localities. And the Romanticists were never weary of extolling the old Shakespearian theatre (where the place represented was simply intimated by a label attached to the scenes) as a higher development of art than that of their own day. The champions of realism in art were at that time advocating the substitution of solid walls for scenes; Schlegel maintained that those who insisted on having three walls on the stage were logically obliged to go a step farther and have a fourth wall, on the side towards the audience.