  We determine the D/H ratio in the interstellar medium toward the DO white
dwarf PG0038+199 using spectra from the Far Ultraviolet Spectroscopic Explorer
(FUSE), with ground-based support from Keck HIRES. We employ curve of growth,
apparent optical depth and profile fitting techniques to measure column
densities and limits of many other species (H2, NaI, CI, CII, CIII, NI, NII,
OI, SiII, PII, SIII, ArI and FeII) which allow us to determine related ratios
such as D/O, D/N and the H2 fraction. Our efforts are concentrated on measuring
gas-phase D/H, which is key to understanding Galactic chemical evolution and
comparing it to predictions from Big Bang nucleosynthesis. We find column
densities log N(HI) = 20.41+-0.08, log N(DI)=15.75+-0.08 and log N(H2) =
19.33+-0.04, yielding a molecular hydrogen fraction of 0.14+-0.02 (2 sigma
errors), with an excitation temperature of 143+-5K. The high HI column density
implies that PG0038+199 lies outside of the Local Bubble; we estimate its
distance to be 297 (+164,-104)pc (1 sigma). D/[HI+2H2] toward PG0038+199 is
1.91(+0.52,-0.42) e-5 (2 sigma). There is no evidence of component structure on
the scale of Delta v > 8 km/s based on NaI, but there is marginal evidence for
structure on smaller scales. The D/H value is high compared to the majority of
recent D/H measurements, but consistent with the values for two other
measurements at similar distances. D/O is in agreement with other distant
measurements. The scatter in D/H values beyond ~100pc remains a challenge for
Galactic chemical evolution.
