[en] Several suggestions have been given that cluster formation must play an important role in high-energy multiparticle physics. In the latter this is proved to be an inescapable consequence of a well-defined mathematical scheme, provided only that the physical total and elastic cross-sections have the same asymptotic behaviour (as the data presently available suggest) and that the mean multiplicity of pions produced is an increasing function of energy. Furthermore it is also proved that, with increasing energy, the mean number of clusters tends to a constant, which is roughly estimated. As a consequence the mass of at least some clusters must increase