  Relative hadron abundances from high-energy heavy-ion collisions reveal
substantial inhomogeneities of temperature and baryon-chemical potential within
the decoupling volume. The freeze-out volume is not perfectly "stirred", i.e.
the concentrations of pions, kaons, (anti-) nucleons etc are inhomogeneous.
Such inhomogeneities in the late stages of the hydrodynamic expansion might be
traces of a first-order phase transition.
