If expression depends thus in part upon the moral and temperamental qualities of the listener, form in equal measure depends upon his mental alertness. «Form,» says Dr. Santayana, «does not appeal to the inattentive; they get from objects only a vague sensation which may in them awaken extrinsic associations; they do not stop to survey the parts or to appreciate their relation, and consequently are insensible to the various charms of various unifications; they can find in objects only the value of material or of function, not that of form.» This is unfortunately the case with many who consider themselves «musical»; they enjoy sweetness of sound and the rather vague emotion music arouses in them, but get no clear sense of its deeper architectural beauty. Like Charles Lamb, they are «sentimentally disposed to harmony, but organically incapable of a tune.» But a thoroughgoing love of music, as will be clear enough by now, must include an appreciation of all its aspects; and since beauty of form is not only delightful in itself, but is a potent means of expression as well, insensibility to it involves the loss of much of what is most precious in music. It is necessary, then, to train the attention, to listen accurately as well as sympathetically, to grasp the thematic phrases as they occur, to remember them when they recur, and to follow them through all their transformations. We should think that man but slightly appreciative of poetry who, after hearing a play of Shakespeare, should say that the words seemed to him mellifluous and that many passages moved him, but that he had not the slightest idea what it was all about. Yet how many of us, after hearing a Beethoven symphony, have the slightest definite idea what it is about? If we would get more than transient, profitless titillation from music, we must cultivate our attention, learning, to borrow a phrase from optics, «to make the image sharp.» As we progress in that faculty we shall constantly see new beauties, which in turn will constantly react to deepen expression; and if we are so fortunate as to have also a nature sensitive, tender, and earnest, fitted to feel the best kind of emotion that can be aroused by sound, we may hope to gain eventually an accurate, intelligent, and deep appreciation of music.