"A symbol," says Comte Goblet d'Alviella, in his book on _The Migration of Symbols,_ "might be defined as a representation which does not aim at being a reproduction." Originally, as he points out, used by the Greeks to denote "the two halves of the tablet they divided between themselves as a pledge of hospitality," it came to be used of every sign, formula, or rite by which those initiated in any mystery made themselves secretly known to one another. Gradually the word extended its meaning, until it came to denote every conventional representation of idea by form, of the unseen by the visible. "In a Symbol," says Carlyle, "there is concealment and yet revelation: hence, therefore, by Silence and by Speech acting together, comes a double significance." And, in that fine chapter of _Sartor Resartus,_ he goes further, vindicating for the word its full value: "In the Symbol proper, what we can call a Symbol, there is ever, more or less distinctly and directly, some embodiment and revelation of the Infinite; the Infinite is made to blend itself with the Finite, to stand visible, and as it were, attainable there." It is in such a sense as this that the word Symbolism has been used to describe a movement which, during the last generation, has profoundly influenced the course of French literature. All such words, used of anything so living, variable, and irresponsible as literature, are, as symbols themselves must so often be, mere compromises, mere indications. Symbolism, as seen in the writers of our day, would have no value if it were not seen also, under one disguise or another, in every great imaginative writer. What distinguishes the Symbolism of our day from the Symbolism of the past; is that it has _now_ become conscious of itself, in a sense in which it was unconscious even in Gérard de Nerval, to whom I trace the particular origin of the literature which I call Symbolist. The forces which mould the thought of men change, or men's resistance to them slackens; with the change of men's thought comes a change of literature, alike in its inmost essence and in its outward form: after the world has starved its soul long enough in the contemplation and the re-arrangement of material things, comes the turn of the soul; and with it comes the literature of which I write in this volume, a literature in which the visible world is no longer a reality, and the unseen world no longer a dream.