THERMAL FITS OF HADRON ABUNDANCES IN HEAVY-ION COLLISIONS

It is shown that the hadron multiplicities measured in central nucleus -nucleus at CERN SPS are in agreement with a hadron gas model suppleme nted with a strangeness suppression parameter ys. The full chemical eq uilibrium version of the model fails to describe the data. The freeze- out temperature of about 180 MeV seems to be independent of the system size (from SI-S to Pb+Pb) and in agreement with that extracted in e() + e(-), p + p and p+(p) over bar collisions. The observed strangenes s enhancement in nucleus-nucleus collisions can not be attributed to t he increased system size at the hadron level.