> The electrifying opening glissando was specially composed
> by Gershwin for Whiteman's agile clarinetist.

The way I heard that part was that the opening run was originally
written as individual notes.  Ross Gorman (I believe he was the
clarinetist) was joking around with it, thus producing the gliss
effect, and Gershwin told him to keep it in.

He may have been mocking Ted Lewis or the klezmer style at the time.
If you listen to the laughing sound in the measures following,
that's what it really sounds like.

George Bogatko
http://www.inluxeditions.com/

 [ My view is that Gershwin knew the sound he wanted from Gorman's
 [ clarinet ("the klezmer sound"), but he didn't know how to notate the
 [ jazz glissando except as a scale of notes (and classically-trained
 [ Ferde Grofe didn't recognize the jazz sound when he copied the
 [ parts).  Witness the difference between recorded jazz solos tran-
 [ scribed in the 1920s, and the same solos written down in contemporary
 [ jazz notation.  Whiteman's core players were indeed fine jazz
 [ musicians, and they produced sounds and effects 'way beyond those
 [ of the typical orchestra.  -- Robbie