  The original version of this paper commented on a paper by Jaffe, Jin, and
Tang (hep-ph/9710561). That paper has been revised, and my original comment no
longer applies to the revised version. The original version of my comment
(hep-ph/9801217v1) provides a simple argument that two-particle correlations in
parity-invariant fragmentation cannot provide a measurement of the helicity of
the fragmenting quark.
