And this is the truth also; and holding this clue you will easily and justly interpret the phenomena of history. So long as Art is steady in the contemplation and exhibition of natural facts, so long she herself lives and grows; and in her own life and growth partly implies, partly secures, that of the nation in the midst of which she is practised. But a time has always hitherto come, in which, having thus reached a singular perfection, she begins to contemplate that perfection, and to imitate it, and deduce rules and forms from it; and thus to forget her duty and ministry as the interpreter and discoverer of Truth. And in the very instant when this diversion of her purpose and forgetfulness of her function take place--forgetfulness generally coincident with her apparent perfection--in that instant, I say, begins her actual catastrophe; and by her own fall--so far as she has influence--she accelerates the ruin of the nation by which she is practised. The study, however, of the effect of art on the mind of nations is one rather for the historian than for us; at all events it is one for the discussion of which we have no more time this evening. But I will ask your patience with me while I try to illustrate, in some further particulars, the dependence of the healthy state and power of art itself upon the exercise of its appointed function in the interpretation of fact. You observe that I always say _interpretation_, never _imitation_. My reason for so doing is, first, that good art rarely imitates; it usually only describes or explains. But my second and chief reason is that good art always consists of two things: First, the observation of fact; secondly, the manifesting of human design and authority in the way that fact is told. Great and good art must unite the two; it cannot exist for a moment but in their unity; it consists of the two as essentially as water consists of oxygen and hydrogen, or marble of lime and carbonic acid.