  We have performed a many-body calculation of the longitudinal nuclear
$(e,e')$ reaction employing a Second RPA (SRPA) formalism which contains the
$\Delta$(1232). More explicitly, our scheme contains RPA correlations as well
as Hartree-Fock and second order self-energies, where an accurate evaluation of
exchange terms is achieved. Using this formalism we have evaluated the
longitudinal response function for $^{40}Ca$. We give final results at momentum
transfers ranging from 300 up to 500 MeV/c, obtaining a good agreement with
data.
