It was an intuitive leap on my part to carry the link to Jackson. It may be wrong but I do not think it is perverse. The kind of almost hypnotic repition used by Whitman and so favored by black preachers evolved, I think, into an art form in the 1870's and 80's (JWJ took inspiration from the published sermons of those days), and it may be that Whitman picked up some of his cadence from the preachers and they from him. --Red Bowen