If an art has boundaries at all--boundaries of its soul-become- form--they are historical and not technical orphysiological boundaries.
...The choice of art-genus itself is seen to be a means of expression. What the creation of a masterpiece means for an individual arts--the "Night Watch" for Rembrandt or the Meistersinger for Wagner--the creation of a species of art, comprehended as such, means for the life-history of a Culture. it is epochal. Apart from the merest externals, each art is an individual organism without predecessr or successor. Its theory, technique and convention all belong to its character, and contain nothing of eternal or universal validity. When one of these arts is born, when it is spent, whether it dies or is transmuted into another, why this or that art is dominant in or absent from a particular Culture--all these are questions of Form in the highest sense, just as is that other question of why individual painters and musicians unconsciously avoid certian shades and harmonies or, on the contrary, show preferences so marked that authorship-attributions can be based on them.
The importance of these groups of questions has not yet been recognized by theory... A futile up-and-down course was stolidly traced out. Static times were described as "natural pauses," it was called "decline" when some great art in reality died, and "renaissance" where an eye really free form prepossessions would have seen another art being born in another landscape to express another humanity.
And yet it is precisely in this problem of the end, the impressively sudden end, of a great art--the end of the Attic drama in Euripides, of Florentine sculpture with Michaelangelo, of instrumental music n Liszt, Wagner, and Bruckner--that the organic character of these arts is most evident. ...