  Particle number fluctuations are studied in relativistic Bose and Fermi
gases. The calculations are done within both the grand canonical and canonical
ensemble. The fluctuations in the canonical ensemble are found to be different
from those in the grand canonical one. Effects of quantum statistics increase
in the grand canonical ensemble for large chemical potential. This is, however,
not the case in the canonical ensemble. In the limit of large charge density a
strongest difference between the grand canonical and canonical ensemble results
is observed.
