The concept of Lorentz scalar quark confinement has a long history and is
still widely used despite its well-known theoretical faults. We point out here
that the predictions of scalar confinement also conflict directly with
experiment. We investigate the dependence of heavy-light meson mass differences
on the mass of the light quark. In particular, we examine the strange and
non-strange D mesons. We find that the predictions of scalar confinement are in
considerable conflict with measured values.Comment: REVTeX4, 7 pages, 4 EPS figure