No literary expression can, properly speaking, be called poetry that is not in a certain deep sense emotional, whatever may be its subject-matter, concrete in its method and its diction, rhythmical in movement, and artistic in form.... That poetry must be metrical or even rhythmical in movement, however, is what some have denied. Here we touch at once the very root of the subject.... While prose requires intellectual life and emotional life, poetry seems to require not only intellectual life and emotional life but rhythmic life.... Unless the rhythm of any metrical passage is so vigorous, so natural, and so free that it seems as though it could live, if need were, by its rhythm alone, has that passage any right to exist? and should it not, if the substance is good, be forthwith demetricized and turned into prose? ... Aristotle ignored, and Plato slighted, the importance of versification (though Plato on one occasion admitted that he who did not know rhythm could be called neither musician nor poet).... On the whole, however, the theory that versification is not an indispensable requisite of a poem seems to have become nearly obsolete in our time. Perhaps, indeed, many critics would now go so far in the contrary direction as to say with Hegel (_Æsthetik_, iii. p. 289) that "metre is the first and only condition absolutely demanded by poetry, yea even more necessary than a figurative picturesque diction." (THEODORE WATTS: Article on "Poetry" in _Encyclopædia Britannica_.) Verse-rhythm in words is the imposition of a _sensible_ order on what naturally and normally has only a _logical_ order; and there is piquancy in the feeling that so little is this ideal control a fettering instrument, that each order seems to gain verve and spontaneity from the other, or rather from the latent sense that the other, though present and operative, is powerless to hamper it. Much more important, however, is it to notice how the sense that one single thing--the word-series--is lending itself to this joint dominance may take the form of a sort of transfigured surprise. (The root-principle here involved is the old one of "unity in variety," the _single_ line of words, "dominated at once by the idea which they express in their grammatical connection and by their metrical adjustment," clearly possessing _two_ independent functions or aspects. See the fuller discussion of "The Sound-element in Verse," in chapter xix. of _The Power of Sound_.) ... When, as in verse, the sounds are pointedly addressed _both_ to the ear and to the understanding, the rarity of the combination of aspects contributes a strain of feeling partly akin to that with which we follow an exhibition of skill, and partly to that with which we receive an unexpected gratuity....