  We describe new optical photometric and spectroscopic observations of the
semi-detached eclipsing binary BG Geminorum. A large change in the amount of Mg
I absorption at secondary maximum indicates the presence of cool material in
the outer edge of the disk surrounding the unseen primary star. Detection of
weak He I emission implies a hot radiation source at the inner edge of the
disk. If the velocity variations in the Hbeta emission line track the orbital
motion of the primary star, the primary star has an orbital semiamplitude of K1
= K(Hbeta) = 16.0 +- 4.6 km/sec. This result yields a mass ratio, q = 0.22 +-
0.07, consistent with the q = 0.1 derived from the large ellipsoidal variation.
Despite this progress, the nature of the primary star - B-type star or black
hole - remains uncertain.
