We analyze all of the cold-collision data for Cs, consisting of atomic
fountain frequency shifts and elastic scattering rates, to determine
phase parameters that completely characterize cold collisions between
two ground-state cesium atoms. We show that the fast decays of spin-po
larized gas samples in two recent attempts to reach Bose-Einstein cond
ensation in cesium are due to potential and Feshbach resonances which
enhance the depolarizing atom-atom collisions. We discuss the prospect
s for realizing Bose-Einstein condensation in Cs-133 and in Cs-135.