  Fluctuations of charged particle number are studied in the canonical
ensemble. In the infinite volume limit the fluctuations in the canonical
ensemble are different from the fluctuations in the grand canonical one. Thus,
the well-known equivalence of both ensembles for the average quantities does
not extend for the fluctuations. In view of a possible relevance of the results
for the analysis of fluctuations in nuclear collisions at high energies, a role
of the limited kinematical acceptance is studied.
