  We present new observations of the binary Sirius A / Sirius B performed with
HST-GHRS. Two interstellar clouds are detected on this sightline, one of them
being identified as the Local Interstellar Cloud (LIC). The interstellar
structure of this sightline is constrained by high spectral resolution data of
the species OI, NI, SiII, CII, FeII and MgII. Lyman alpha interstellar lines
are also observed toward the two stars. But whereas the deuterium Lyman alpha
line is well detected in the LIC with an abundance in agreement with that
obtained by Linsky et al. (1993 & 1995), no significant DI line is detected in
the other cloud.
  However, the Lyman alpha lines toward Sirius A and Sirius B are not trivial.
An excess of absorption is seen in the blue wing of the Sirius A Lyman alpha
line and interpreted as the wind from Sirius A. In its white dwarf companion,
an excess in absorption is seen in the red wing and interpreted as the core of
the Sirius B photospheric Lyman alpha line. A composite Lyman alpha profile can
nonetheless be constructed, and allows one to measure the deuterium abundance
in the second cloud 0 < D/H_ISM < 1.6 10^-5, which is marginally in agreement
with the Linsky et al. (1993 & 1995) value. This sightline appears consequently
as a good candidate for a low D/H_ISM.
