  The scattering effects of charm mesons by hadrons such as the pion, rho meson
and nucleon are studied in an effective Lagrangian, and are found to be
important in heavy ion collisions. At the CERN-SPS energies, hadronic
rescatterings are shown to harden the charm meson $m_T$ spectra, leading to a
significant enhancement of the yield of intermediate-mass dimuons from charm
meson decays.
