  We identify the X-Ray reflected component in the Ginga spectra of Nova Muscae
1991, a Black Hole transient system used as the prototype for the recent model
of Esin, McClintock & Narayan (1997) based on advection dominated disk
solutions. We see that the reflected spectrum is generally significantly
relativistically smeared, and use this, together with the amplitude of
reflection, to track the innermost extent of the accretion disk. The optically
thick disk switches from being highly ionized to nearly neutral during the
transition from high to low state, and the inner radius of the disk moves
outwards during the low state decline. Qualitatively, this overall trend is
compatible with Esin et al.'s model, but quantitatively, the retreat of the
inner disk during the high to low state transition is much slower than
predicted. The hard (low state) spectra are not produced solely by an optically
thin accretion flow: optically thick material within 20-100 Rg is generally
present.
