Since that day when, a quarter of a century ago, Richard Wagner ceased to be a dynamic figure in the life of the world, the history of operatic art has been, save for a few conspicuous exceptions, a barren and unprofitable page; and it has been so, in a considerable degree, because of him. When Mr. William F. Apthorp, in his admirable history of the opera-a book written with unflagging gusto and vividness-observed that Wagner's style has been, since...