Read it through once

The initial consideration was that of extent. If any literary work is too long to be read at one sitting, we must be content to dispense with the immensely important effect derivable from unity of impression—for, if two sittings be required, the affairs of the world interfere, and everything like totality is at once destroyed. But since, ceteris paribus, no poet can afford to dispense with anything that may advance his design, it but remains to be seen whether there is, in extent, any advantage to counterbalance the loss of unity which attends it. Here I say No, at once. What we term a long poem is, in fact, merely a succession of brief ones—that is to say, of brief poetical effects. It is needless to demonstrate that a poem is such, only inasmuch as it intensely excites, by elevating, the soul; and all intense excitements are, through a psychal necessity, brief. For this reason, at least one-half of the “Paradise Lost” is essentially prose—a succession of poetical excitements interspersed, inevitably, with corresponding depressions—the whole being deprived, through the extremeness of its length, of the vastly important artistic element, totality, or unity, of effect.