  This paper follows on from a previous one in which it was shown that it is
possible, within a de Broglie-Bohm style ontology for quantum mechanics, to
incorporate action and reaction between the particle and its guiding field
while remaining consistent with the usual experimental predictions. Whereas the
previous paper focussed on the Dirac equation, the present work addresses the
Schrodinger case and demonstrates that the same two-way interaction can be
achieved. The aim in each case is to increase the physical plausibility of such
models. The transition to include the reaction of the particle back on the
field, and hence energy and momentum conservation, is attained by employing
standard Lagrangian techniques. In formulating this description an interesting
bonus emerges in that the hitherto unrelated concept of a gauge transformation
is found to arise naturally as an essential part of the formalism. In
particular, the phase S of the gauge transformation is seen to be the action
function describing the hidden motion of the particle.
