Few, if any, of the great masterpieces of literature, even of those which bear the most unmistakable imprint of an original mind, are 'original' in the vulgar sense of being invented 'all out of the head' of the author. Most frequently they are the development and the sublimation of forms and subjects already current; for, as Dumas pere truly said, it is mankind, and not the individual man, that invents. The wagon of Thespis preceded the stage of...