  We calculated the contribution of internal nucleon electric dipole moments to
the Schiff moment of $^{199}$Hg. The contribution of the proton electric dipole
moment was obtained via core polarization effects that were treated in the
framework of random phase approximation with effective residual forces. We
derived a new upper bound $|d_p|< 5.4\times 10^{-24} e\cdot$cm of the proton
electric dipole moment.
