  The monopole-like singularity of Berry's adiabatic phase in momentum space
and associated anomalous Poisson brackets have been recently discussed in
various fields. With the help of the results of an exactly solvable version of
Berry's model, we show that Berry's phase does not lead to the deformation of
the principle of quantum mechanics in the sense of anomalous canonical
commutators. If one should assume Berry's phase of genuine Dirac monopole-type,
which is assumed to hold not only in the adiabatic limit but also in the
non-adiabatic limit, the deformation of the principle of quantum mechanics
could take place. But Berry's phase of the genuine Dirac monopole-type is not
supported by the exactly solvable version of Berry's model nor by a generic
model of Berry's phase. Besides, the monopole-like Berry's phase in momentum
space has a magnetic charge $e_{M}=2\pi\hbar$, for which the possible anomalous
term in the canonical commutator $[x_{k},x_{l}]=i\hbar\Omega_{kl}$ would become
of the order $O(\hbar^{2})$.
