Beethoven, in fact, had brought a new spirit into the symphony and the overture without being able to discover a new and inevitable form in which this spirit could express itself. Wagner from his earliest years must have felt that he too had a dim perception of a new world of expression, if only he could discover the form for it. That form clearly did not exist in the symphony even as Beethoven had left it, for Wagner\'s vision was ready to take a bolder poetic flight even than Beethoven\'s, and it would have been as sadly hampered by the more freely symphonic but still largely formal method of Beethoven as the latter had been by the traditions of form he had taken over from his predecessors. It was still more useless for Wagner to seek the new logic of form in the other great art-genre of his day—the opera—for here illogic reigned supreme. The opera not only did not achieve the unity it professed to aim at; it did not even let either of its two great and ever warring constituents tyrannise effectively over the other. Instead, each merely lamed the other; the average opera was neither a good play spoiled by music, nor good music spoiled by a play, but merely a bad play and formless music adding each to the other\'s foolishness. How hopelessly impotent the current opera was to furnish a form that should be adequate for all that a modern musician might have to say was shown by the practice of Beethoven: the greatest musical brain of its epoch turned in anger and disappointment and disgust from the opera after one experiment with it, and concentrated more and more on the symphonic forms, endeavouring to make these more expansive and more flexible.

A hundred composers and theorists had for a century past realised the insufficiency of the opera. Gluck\'s manifestos are known to every student. More than a generation after Gluck the same problems were still being discussed in virtually the same terms and with the same results. Theory was evidently a long way ahead of practice; but even theory failed because it missed just the one seminal thing that it was Wagner\'s function to bring to light. The excellencies and the final limitations of the theory of the time are best seen in a rather remarkable work—Ignaz Franz Mosel\'s Versuch einer Aesthetik des dramatischen Tonsatzes ("Attempt at an ?sthetic of the Musical Drama")—that, curiously enough, was published in the year of Wagner\'s birth.[382] Much in this book might have been written by Gluck; some of it might even have been written by Wagner himself. Mosel expresses more clearly perhaps than any previous writer that conception of the unified art-work upon which Wagner so strongly insisted. For Mosel the ideal opera is a combination, on practically equal terms, of poetry, music, acting, singing and the art of the stage; the plastic arts, however, play a smaller part in his theory than they do in Wagner\'s. He regards the drama as the basis of opera. He sees, as Wagner did, that the rules of procedure of pure music are not applicable in their entirety to the dramatic stage. Like Wagner, again, he holds that complicated subjects, founded on intrigue or political action, are unsuitable for opera. Music being a purely emotional art, addressing itself more to the heart than the head, the best subject is that that gives full play to the emotional power of tone. The best subjects are the mythological ones. The poet must so shape his text that it is "thoroughly musical, that is, not only containing nothing that is outside the possibility of musical expression, but also nothing to which music cannot give a heightened beauty and a strengthened effect." The verse should be of such a kind that the composer\'s melody can spring naturally out of it. As a rule one syllable should be set to one note only. The melody must rise or fall precisely at the point where a good declaimer of the verses who is not musical would make them do so. Mosel sees that dramatic music frequently demands a different method of structure from that of pure music; as he puts it, the so-called musical period of two, four or eight-bar melodies can often be departed from with advantage. The style of the music as a whole must vary with the quality of the poetic subject; and not only must the general nature of the theme be reproduced in music, but also the physical, moral or conventional character of each person; and this adaptability of style to subject must be preserved in the orchestra as well as in the voice. The overture, having for its subject the preparation of the hearer for what is to come, must bear the same character as that which is dominant in the opera itself. There must be as little distinction as possible between recitative and aria. Form and expression must always follow the feeling. And so on and so on.

This was the sole result of a hundred years of keen theory and ardent practice. The form of opera remained virt............