Thanks, Don. That places the suggestion a bit further back and in more informed hands than the other thread had revealed, so my comment "fanciful modern nonsense" should now be disregarded. "Fanciful" stands, though, until someone comes up with references we can check up on. If you do ever happen to unearth those class notes, please do let us know. There must be an awful lot of useful stuff like that out there, perhaps from sources that never made it into print.

It's high time I read Fowler's Literary History of the Popular Ballad. A visit to the library tomorrow is in order, I think.