  We present an observation of the very late thermal pulse object V4334 Sgr
(Sakurai's Object) with the Infrared Spectrometer (IRS) on the Spitzer Space
Telescope. The emission from 5-38 microns is dominated by the still-cooling
dust shell. A number of features are seen in absorption against the dust shell,
which we attribute to HCN and polyyne molecules. We use these features to
determine the 12C/13C ratio for the absorbing gas to be ~ 3.2 (+3.2,-1.6}; this
implies that, despite the H-content of the molecules, the hydrocarbon-bearing
gas must have originated in material produced in the very late thermal pulse.
We see no evidence of emission lines, despite the recently-reported optical and
radio observations that suggest the effective temperature of the stellar
remnant is rising.
