  If the pomeron is generated by a two gluon exchange there is no a priori
reason for a drastic suppression of three gluon exchange with negative parity
and charge parity. This would lead to an unacceptably large difference between
$p\,p$ and $p\, \bar{p}$ scattering. It is shown that a natural suppression of
the $C$=$P$=--1 contribution to high energy scattering is given by a cluster
structure of the nucleon.
