Within this limit alone can the highest order of true poetry exist. We need only here say, upon this topic, that, in almost all classes of composition, the unity of effect or impression is a point of the greatest importance. It is clear, moreover, that this unity cannot be thoroughly preserved in productions whose perusal cannot be completed at one sitting. We may continue the reading of a prose composition, from the very nature of prose itself, much longer than we can persevere, to any good purpose, in the perusal of a poem. This latter, if truly fulfilling the demands of the poetic sentiment, induces an exaltation of the soul which cannot be long sustained.
All high excitements are necessarily transient.
Thus a long poem is a paradox. And, without unity of impression, the deepest effects cannot be brought about. Epics were the offspring of an imperfect sense of Art, and their reign is no more. A poem too brief may produce a vivid, but never an intense or enduring impression. There must be the dropping of the water upon the rock.