  We show that the Dual String Model with fusion leads, in heavy ion
collisions, to strict saturation of the particle (pseudo-)rapidity density,
normalised to the number of participant nucleons, as that number increases.
Asymptotically, as the centre-of-mass energy goes to infinity with the number
of participants fixed, this density approaches the nucleon-nucleon density.
  A comparison with recent WA98 data is presented.
