  In the context of the quark model of hadrons the spin and the magnetic moment
of proton can not be taken proportional. This is in contradiction with the
widely used relation between these two properties of the proton. This apparent
difficulty is addressed by the most elementary notions of the relevant physics.
In particular it is emphasized that the widely used relation is only valid in
the lowest orders of perturbation, in which transitions between different
baryons do not occur. For other processes where such transitions do occur, such
as inelastic scattering off the protons, the quark model relation for the
magnetic moment is used to give an estimation for the amplitude of transition
between states with different total spins.
