(_a_) Human art should in all its associations place us on a ground quite other than that we confront in ordinary life, or indeed in our religious consciousness, active life, or the speculations of philosophy. This is possible on the side of literary or verbal expression only in so far as another mode of speech is adopted than that obtaining in those other spheres. Art has therefore not only, from one point of view, to avoid that in its instrument of expression which will fail to rise above the trivialities of ordinary speech and ordinary prose, but it must, furthermore, avoid falling into the tone and manner of religious edification and philosophical research. Above all it must keep aloof from the precise analyses and _methods_ of the scientific faculty, the categories of pure thinking as we find these illustrated in the logical forms of judgment and deduction. These at once remove art from the imaginative realm to another region altogether. But in all these respects it still remains a difficult matter to determine the lines of boundary on which we may actually affirm that poetry ends and prose begins. And in fact we may admit absolute precision and confidence of statement to be impossible from the nature of the case. (_b_) If we pass now to a discussion of the particular _means_ which poetic-speech can appropriate as instrumental to its task the following points appear to me pregnant and suggestive. (_α_) _First_, we find particular _words_ and exclamations[5] that are obviously peculiar to poetry, whether they be used to ennoble it, or to introduce the vulgarity and excess of comedy. We find a similar novelty in the specific collocation of various words or turns of expression. In such a field poetry is no doubt entitled on the one hand to borrow from an obsolete nomenclature, obsolete at least in everyday speech, and on the other to declare itself as pre-eminently an innovator, moulding novel modes of speech. Such a field, provided only the vital genius of the language is preserved, supplies material for astonishing boldness of invention.