  The thermal conductivity \kappa of Bi-2212 is measured in pure and Zn-doped
crystals as a function of temperature and magnetic field. The in-plane
resistivity is also measured on the identical samples. Using these data, we
make a crude estimate of the impurity-scattering rate \Gamma of the pure and
the Zn-doped crystals. Our measurement show that the "plateau" in the \kappa(H)
profile is not observed in the majority of our Bi-2212 crystals, including one
of the cleanest crystals available to date. The estimated values of \Gamma for
the pure and Zn-doped samples allow us to compare the \kappa(H) data with the
existing theories of the quasiparticle heat transport in d-wave superconductors
under magnetic field. Our analysis indicates that a proper inclusion of the
quasiparticle-vortex scattering, which is expected to play the key role in the
peculiar behavior of the \kappa(H), is important for a quantitative
understanding of the QP heat transport in the presence of the vortices.
