  The force densities exerted on a localised material system by linearised
interaction with fields of axionic and dilatonic type are shown to be
describable very generally by relatively simple expressions that are well
behaved for fields of purely external origin, but that will be subject to
ultraviolet divergences requiring regularisation for fields arising from self
interaction in submanifold supported ``brane'' type systems. In the particular
case of 2-dimensionally supported, i.e. string type, system in an ordinary
4-dimensional background it is shown how the result of this regularisation is
expressible in terms of the worldsheet curvature vector $K^\mu$, and more
particularly that (contrary to what was suggested by early work on this
subject) for a string of Nambu Goto type the divergent contribution from the
dilatonic self action will always be directed oppositely to its axionic
counterpart. This makes it possible for the dilatonic and axionic divergences
to entirely cancel each other out (so that there is no need of a
renormalisation to get rid of ``infinities'') when the relevant coupling
coefficents are related by the appropriate proportionality condition provided
by the low energy limit of superstring theory.
