The prelude is the only operatic prelude in the world which is an integral, organic part of the drama; it cannot be omitted without detriment to the drama. In several of Mozart's operas the overture, by means of a modulation, is made to lead without a break into the first scene; Gluck had done precisely the same thing; Wagner, in the _Mastersingers of Nuremberg_, did the same thing. But in the cases of Gluck and Mozart and of Wagner in the _Mastersingers_, if by chance the parts of the overture were missing, the opera could start away and go on merrily, and we should miss nothing but the preliminary pleasure of hearing the overture. In the case of _Tristan_, where Wagner's art of combining the music and drama in an indivisible whole was at its culminating point--a point from which it gradually receded--this is not conceivable. If the band parts of the _Tristan_ prelude were mislaid it would be well to omit the first act altogether. What Wagner tried to do in the _Flying Dutchman_--to make the whole opera a solid thing from which not one bar might be subtracted without ruining the whole effect--he achieved once, and once only, in _Tristan_. What may seem an irrelevancy turns on this very point. There is no necessity for reasoning about a work of art; yet there is both pleasure and mental profit in doing so in certain instances. If there is any necessity at all for understanding Wagner's mind and Wagner's art, we may as well do it as thoroughly as we can. Therefore the reader will perhaps bear with me patiently if I point out something he has doubtless discovered for himself, namely, that _Tristan_ is Wagner's only opera in which music and drama had birth simultaneously in his brain. He himself, in several significant passages in his prose writings, indicated this. He said that when, after several years devoted to expounding his theories in essays,--mainly, he said, to make these theories clear to himself: mainly, I think, for the accruing cash--he began _Tristan_, he immediately found he had left the theories far behind. That is, he constructed his dramas, without thinking of theories or traditions, simply as a common-sense dramatist-musician should, building up the whole edifice with two hands at once, the dramatist's pen in one hand, the musician's in the other. He also said that when he set down the words the music was already (in an amorphous state--we must presume he meant) in his brain. It was to this effect he wrote in _Opera and Drama_ the most skilful defence ever put together by a creative artist--or rather not so much a defence as a plea for his particular form of art, or perhaps an explanation of the form.