  First post-Newtonian (PN) approximation of the scalar-tensor theory of
gravity is used to discuss the effacing principle in N-body system, that is
dependence of equations of motion of spherically-symmetric bodies comprising
the system on their internal structure. We demonstrate that the effacing
principle is violated by terms which are proportional to the second order
rotational moment of inertia of each body coupled with \beta-1, where \beta is
the measure of non-linearity of gravitational field. In case of general
relativity, where \beta=1, the effacing principle is violated by terms being
proportional to the rotational moment of inertia of the forth order. For
systems made of neutron stars (NS) and/or black holes (BH) these terms
contribute to the orbital equations of motion at the level of the third and
fifth PN approximation respectively.
