  This paper presents an analysis of the UV spectrum of some nebulae with
clearly identified illuminating stars, all observed by the IUE satellite.
  The data show remarkable properties of the UV spectrum of the nebulae. Each
spectrum is the product of the star spectrum and a linear function of 1/lambda.
There is no peculiar behaviour in the spectrums at 2200A: no bump created in
the spectrum of a nebula and no excess of scattering. When moving away from the
star, the surface brightness of a nebula decreases as the inverse of the square
of the angular distance to the star.
  These results can logically be interpreted in terms of scattering of
starlight. They imply constant properties of the interstellar grains in the UV
and in the directions of space sampled by the nebulae, and probably a strong
forward scattering phase function. There is no evidence for any particular type
of grain which would specifically extinguish starlight at 2200A.
  Concerning the UV spectrum of a star, this may imply a revisal of the
traditional interpretation of the 2200A bump.
