The arts themselves, as well as their subordinate forms, are closely related to each other, and have a certain tendency to unite, and even lose themselves in each other; but herein lies the duty, the merit, the dignity of the true artist, that he knows how to separate that department in which he labors from the others, and, so far as may be, isolates it. It has been noticed that all plastic art tends towards painting, all poetry to the drama; and this may furnish the text for some important observations hereafter. The genuine, law-giving artist strives after artistic truth; the lawless, following a blind instinct, after an appearance of naturalness. The former leads to the highest pinnacle of art, the latter to its lowest step. This is no less true of the separate arts than of art in general. The sculptor must think and feel differently from the painter, and must go to work differently to execute a work in relief from what he would do with a round and complete piece of statuary. When the work in low relief came to be brought out more and more, and by degrees parts and figures were brought out from the ground, at last buildings and landscapes admitted, and thus a work produced, half picture half puppet-show, true art was on the decline; and it is to be deplored that excellent artists have in more recent times taken this direction. Whenever we enunciate hereafter such maxims as we esteem true, we shall feel a real desire, since these maxims are drawn from works of art, to have them practically tested by artists. How seldom does one man agree with another concerning a theoretic principle; the practical and immediately useful is far more quickly adopted. How often do we see artists at a loss in the choice of a subject, in the general composition, according to their rules of art, in the arrangement of details; the painter doubtful about the choice of his colors! Then is the time to make trial of a principle; then will it be easier to decide the question,--Do we by its aid come nearer to the great models, and all that we love and prize, or does it forsake us in the empirical confusion of an experiment not thoroughly thought out? If such maxims should prove useful in forwarding the culture of artists, in guiding them among difficulties, they will also aid the understanding, true estimation, and criticism of ancient and modern works, and, _vice versa_, will again be discovered in the examination of these works. This is all the more necessary, since, in spite of the universally acknowledged excellence of the antique, individuals as well as whole nations have in modern times often misconceived those very things wherein the highest excellence of those works lies.