  We perform the matching required to compute the leading effective boundary
contribution to the QED lagrangian in the presence of a conducting surface,
once the electron is integrated out. Our result resolves a confusion in the
literature concerning the interpretation of the leading such correction to the
Casimir energy. It also provides a useful theoretical laboratory for
brane-world calculations in which kinetic terms are generated on the brane,
since a lot is known about QED near boundaries.
