The multiplicity distribution for charged secondaries emitted from pp, π±p, pn, π±n, nn, K+p and p - p collisions was found to define a single set of curves which can be expressed by a universal set of «multiplicity distribution functions» constructed from Poisson terms when conservation laws are suitably incorporated. The ΛK0 accompanying the pions produced in π-p collision, and the neutrals (mostly π0) produced in π-p inelastic charge-exchange reactions were also found to follow the same distribution. The distribution functions so obtained contain no adjustable parameter and fit well the N N cosmic-ray jet data. The Poissonian characteristic of the multiplicity regularity found points immediately to the existence of a number of nearly independent production regions or «cells» inside the nucleon (and other hadrons), and the fireball. © 1969 Società Italiana di Fisica.