  We present the first spatially resolved spectroscopic observations of the
recently discovered quadruple QSO and gravitational lens HE0435-1223. Using the
Potsdam Multi-Aperture Spectrophotometer (PMAS), we show that all four QSO
components have very similar but not identical spectra. In particular, the
spectral slopes of components A, B, and D are indistinguishable, implying that
extinction due to dust plays no major role in the lensing galaxy. While also
the emission line profiles are identical within the error bars, as expected
from lensing, the equivalent widths show significant differences between
components. Most likely, microlensing is responsible for this phenomenon. This
is also consistent with the fact that component D, which shows the highest
relative continuum level, has brightened by 0.07 mag since Dec 2001. We find
that the emission line flux ratios between the components are in better
agreement with simple lens models than broad band or continuum measurements,
but that the discrepancies between model and data are still unacceptably large.
Finally, we present a detection of the lensing galaxy, although this is close
to the limits of the data. Comparing with a model galaxy spectrum, we obtain a
redshift estimate of z_lens=0.44+-0.02.
