  Particle number fluctuations are considered within the van der Waals (VDW)
equation, which contains both attractive (mean-field) and repulsive
(eigenvolume) interactions. The VDW equation is used to calculate the scaled
variance of particle number fluctuations in generic Boltzmann VDW system and in
nuclear matter. The strongly intensive measures $\Delta[E^*,N]$ and
$\Sigma[E^*,N]$ of the particle number and excitation energy fluctuations are
also considered, and, similarly, show singular behavior near the critical
point. The $\Delta[E^*,N]$ measure is shown to attain both positive and
negative values in the vicinity of critical point. Based on universality
argument, similar behavior is expected to occur in the vicinity of the QCD
critical point.
