Bluesy cornetist Chris Kelly, most popular with the downtrodden and ratty, “always ended his performances with the hymn ‘When the Saints Go Marching In,’ played, contrary to modern practice, as a ‘sacred song’—slowly” (p. 169).
From Subversive Sounds: Race and the Birth of Jazz in New Orleans by Charles B. Hersch (University of Chicago Press, 2008, pages 180-182):
The small group transformation of ragtime through the blues tradition, hauling it onto the streets where it marched, can be seen in a performance of High Society Rag by King Oliver’s Creole Jazz Band, featuring a young Louis Armstrong. This tune defined New Orleans jazz, for as Lee Collins put it, ‘at that time when you heard a clarinet play High Society you didn’t ask him where he was from. You knew he was from New Orleans …’