  In this short communication we point out to the possibility that the clouds
of the negative vacuum energy around galaxies may have the same effect as dark
matter. These clouds amplify the force acting on the baryonic matter around
galaxies changing their dynamical and kinematical properties. Inserting the
density of the baryonic matter into field equations of the cosmic quaternionic
field for the present time yields the negative cosmological constant which is
approximately equal to the density of the baryonic matter of galaxies. Due to
the effect of the negative vacuum energy on moving cosmical objects the
effective total masses of galaxies assume several times larger values as their
baryonic masses.
