Italian opera was moulded to its present form chiefly by Gluck, before whose time it was less irrational than it became later.  In the beginning it was music-drama of a pedantic kind; then it served as the opportunity for setting singers to deliver a series of beautiful songs for the delectation of an audience largely seated in the wings; and finally Gluck, with his immense dramatic instinct and lack of lyrical invention, saw that by securing a story worth the telling, and telling it well, and inserting songs and concerted pieces only in situations where strong feelings demanded expression, and making his songs truthful expressions of those feelings, a form might be created which would enable him to lever out the best that was in him.  Of these three periods of opera, the second was the luckiest; for then the form entirely fulfilled its purpose.  The sole function of the story was to provide a motive for song after song; so that no one was scandalised or moved to laughter when the death of the hero was re-enacted because his death-song pleased the audience, or when the telling of the story was interrupted on any other equally ridiculous pretext.  The characters were the merest puppets, or shadows of puppets; and there was no reason why Julius Caesar should not be a male soprano and sing charmingly feminine florid airs.  In a word, there was no drama nor pretence of drama in the old Italian form; and those who can accept it as it is will find in many old Italian writers some perfect music of its sort, and in the Italian operas of Handel the divinest songs ever written—­songs even more divine than Mozart’s.  But the childish delight in lovely melodies and in absolute perfection of vocal art, at its highest in the early part of the eighteenth century, died out rapidly after 1750; and Italian opera became the medium of the vulgarest instead of the most refined kind of ear-tickling.  How Gluck rebelled, and determined to “reform” the opera stage, and how in reforming it he was impelled to a large extent by a desire to find a medium through which he could express himself, are matters well enough known to everyone nowadays.  Like every other teacher, he left no disciples; for Mozart, the next master of Italian opera, was a hundred thousand miles away from him in intention, in method, and in achievement.  He commenced where Gluck ended his pre-Reformation period; and all his life his intention was to please first, and only in the second place to express himself.  But so splendid were his gifts, so inevitably did he fit the lovely word to the thrilling thought, so lucky was he in the libretto of “Don Giovanni” (the luckiest libretto ever devised), that he went clean ahead not only of Gluck but of Beethoven and every composer who has written opera since.