  We present the status of the description of hadron production in central
nucleus-nucleus collisions within the statistical model . Extending previous
studies by inclusion of very high-mass resonances (m>2 GeV), and the up-to-now
neglected scalar $\sigma$ meson leads to an improved description of the data.
In particular, the hitherto poorly reproduced energy dependence of the K+/pi+
ratio at SPS energies ("the horn") is now well described through the connection
to the hadronic mass spectrum and, implicitly, Hagedorn's limiting temperature.
