  The chiral extrapolation of the nucleon mass, M_n, is investigated using data
coming from 2-flavour partially-quenched lattice simulations. A large sample of
lattice results from the CP-PACS Collaboration is analysed using the leading
one-loop corrections, with explicit corrections for finite lattice spacing
artifacts. The extrapolation is studied using finite range regularised chiral
perturbation theory. The analysis also provides a quantitative estimate of the
leading finite volume corrections. It is found that the discretisation,
finite-volume and partial quenching effects can all be very well described in
this framework, producing an extrapolated value of M_n in agreement with
experiment. Furthermore, determinations of the low energy constants of the
nucleon mass's chiral expansion are in agreement with previous methods, but
with significantly reduced errors. This procedure is also compared with
extrapolations based on polynomial forms, where the results are less
encouraging.
