Those among my readers who have stood in a room lined with mirrors, and seen themselves and everything else reflected _ad infinitum_, above, below, on every side, have some idea of the vertigo which the study of Romantic art at times produces. Every one who has read Holberg's _Ulysses von Ithacia_ remembers how droll the effect is when the characters, as they are perpetually doing, make fun of themselves and what they represent--when, for example, Ulysses exhibits the long beard which has grown during the ten years' campaign, or when we read upon a screen, "This is Troy," or when, at the close, the Jews rush in and tear off the actor's back the clothes which he had borrowed to play Ulysses in. Histrionic art, as every one knows, depends for its effect upon illusion. And illusion is an aim common to many of the arts. A statue and a painting deceive quite as much as a play, the illusion being contingent upon our momentarily taking the stone for a human being, and the painted flat surface for receding reality, in exactly the same way as we forget the actor in his rôle. This illusion, however, is only complete for a moment. It is, indeed, possible for the perfectly uneducated man to be entirely deceived. An Indian soldier in Calcutta shot an actor who was playing the part of Othello, exclaiming: "It shall never be said that a negro murdered a white woman in my presence!" But in the case of the educated man, the illusion comes and goes; it comes at the moment when the tragedy brings tears into his eyes, and goes at the moment when he draws out his pocket-handkerchief and looks at his neighbour. The effect of the work of art is, as it were, focussed in this illusion. The illusion is the reflection of the work of art in the spectator's mind--the appearance, the play, by means of which the unreal becomes reality to the spectator. In the simple, straightforward work of art no special attention is devoted to illusion; it is not aimed at; nothing is done to strengthen it or to give it piquancy; but still less is anything done to destroy it. It is not difficult, however, to understand how a certain piquant quality may be communicated to the illusion produced by any art. When, for instance, a Hermes, or any idol, is represented on a bas-relief, when a picture represents a studio or a room with pictures hanging on the walls, a strong indication is hereby conveyed that the bas-relief itself is not intended to affect us as statuary, nor the pictures as painting. And the same sort of effect is produced when one or other of the characters in a comedy cries: "Do you take me for a stage-uncle?"