  Cosmological solutions of the Brans-Dicke theory are investigated by
including a quantum effect coming from 1-loop correction of matter fields that
couple to the scalar field. As the most serious result we face a cosmological
``constant'' in the original conformal frame which is shown to be ``physical''
after a careful analysis of the time variable employed in any of the
conventional approaches. We find an ``attractor'' solution featuring no
expansion during the radiation-dominated eras. To evade this unacceptable
consequence, we suggest to modify one of the fundamental premises of the model,
rendering the scalar field almost ``invisible.''
