"not withstanding Joseph's claim, it seems to indicate that Blues had been around for a long time before 1910" I consider the "Got No More Home Than A Dog" that Handy said he heard about 15 years before 1910 to be blues music. No one was _calling_ music like that "blues music" until about 1909.

If the author of the July 11, 1915 Chicago piece actually thought "Blues Is Jazz and Jazz Is Blues," he didn't know much about the music: about how "High Society" as played by Alphonse Picou differed from "All Out And Down" as played by Mance Lipscomb, for instance.