Even in poetry the same thing holds.  Like music, poetry has its root in those natural modes of expression which accompany deep feeling.  Its rhythm, its strong and numerous metaphors, its hyperboles, its violent inversions, are simply exaggerations of the traits of excited speech.  To be good, therefore, poetry must pay attention to those laws of nervous action which excited speech obeys.  In intensifying and combining the traits of excited speech, it must have due regard to proportion—­must not use its appliances without restriction; but, where the ideas are least emotional, must use the forms of poetical expression sparingly; must use them more freely as the emotion rises; and must carry them to their greatest extent, only where the emotion reaches a climax.  The entire contravention of these principles results in bombast or doggerel.  The insufficient respect for them is seen in didactic poetry.  And it is because they are rarely fully obeyed, that so much poetry is inartistic.

Not only is it that the artist, of whatever kind, cannot produce a truthful work without he understands the laws of the phenomena he represents; but it is that he must also understand how the minds of spectators or listeners will be affected by the several peculiarities of his work—­a question in psychology.  What impression any art-product generates, manifestly depends upon the mental natures of those to whom it is presented; and as all mental natures have certain characteristics in common, there must result certain corresponding general principles on which alone art-products can be successfully framed.  These general principles cannot be fully understood and applied, unless the artist sees how they follow from the laws of mind.  To ask whether the composition of a picture is good is really to ask how the perceptions and feelings of observers will be affected by it.  To ask whether a drama is well constructed, is to ask whether its situations are so arranged as duly to consult the power of attention of an audience, and duly to avoid overtaxing any one class of feelings.  Equally in arranging the leading divisions of a poem or fiction, and in combining the words of a single sentence, the goodness of the effect depends upon the skill with which the mental energies and susceptibilities of the reader are economised.  Every artist, in the course of his education and after-life, accumulates a stock of maxims by which his practice is regulated.  Trace such maxims to their roots, and they inevitably lead you down to psychological principles.  And only when the artist understands these psychological principles and their various corollaries can he work in harmony with them.

We do not for a moment believe that science will make an artist.  While we contend that the leading laws both of objective and subjective phenomena must be understood by him, we by no means contend that knowledge of such laws will serve in place of natural perception.  Not the poet only, but the artist of every type, is born, not made.  What we assert is, that innate faculty cannot dispense with the aid of organised knowledge.  Intuition will do much, but it will not do all.  Only when Genius is married to Science can the highest results be produced.