Courtesy of Larry Liberson:

A brief excerpt from The Music for Accompanied Clarinet Solo of Claude Debussy: An Historical Analytical Study of the "Premiere Rhapsodie" and "Petite Piece" by Dennis Quentin Nygren, 1982, Northwestern University.

You should be able to secure a copy of this from:

University Microfilms
300 N. Zeeb Road
Ann Arbor, MI 48106

"One further example concerns the controversial notation in m. 201. [...] displays this measure as it appears in (1) the clarinet/piano autograph, (2) the Durand clarinet/piano edition, (3) the orchestral autograph, and (4) the Durand orchestral score. [...] in three of the four examples the first two notes of the triplet on beat three are notated D#-E natural (written); only in the earlier Durand print (2), first published in 1910, does the pattern appear as it has been played by most clarinetists over the last seventy years (D natural-E flat). Which notation represents the composer's intentions?

The "traditional" approach would favor the D natural-E flat notation. This note sequence is heard in the majority of recorded interpretations, including the earliest recording by E. Gaston Hamelin. Hamelin apparently played the "Rhapsodie" for Debussy, and he also performed the Paris premiere of the orchestrated version shortly after the composer's death. Guy Deplus, who favors the "traditional" notation, informed this investigator that Hamelin was a "very serious, scrupulous, and organized man." He also argues that

"the first performance with piano was at the Paris Conservatory, for the concours held at the end of the school year [July, 1910], and that Debussy was on the jury. The piece was played [eleven times] from the clarinet part edited by Durand, with the notes D natural-E flat, and one continues to always play it in this manner."

A strong argument could also be made for the D#-E natural notation, as it appears in both autographs and the Durand orchestral score. Debussy had Durand send him a copy of the "Rhapsodie" (logically, the clarinet/piano edition, rather than the autograph), so that he could complete the orchestration while vacationing in August 1911. Why would the composer change the notation in his orchestral autograph from the way it appears in the printed clarinet/piano edition, if not to correct an error? It also seems unlikely that Debussy made the same error in both autographs.

One could also support this notation for purely musical reasons. D#-E natural-G natural is the inversion of the last three notes of cell 1. This exact cellular variant appears in the score many times, most notably in the "cedez", m. 123, and enharmonically spelled (E flat-F flat-G natural), in m. 203. In addition, it is difficult to justify the concert C of the printed edition because this pitch is not part of the underlying harmony. The striking dissonance of this C is not consistent with Debussy's coordination of melodic and harmonic elements.

Ernest Ansermet and Pierre Boulez selected the D#-E natural notation for their recordings with the clarinetists, Robert Gugholz and Gervase dePeyer, respectively. Boulez and clarinet soloist, Robert Marcellus, also introduced American audiences to this less familiar notation on a Cleveland Orchestra tour in 1969."