The recent detections of a large population of faint submillimetre sources , an excess halo \gamma -ray background , and the extreme scattering events observed for extragalactic radio sources have been explained as being due to baryonic dark matter in the form of small , dark , gas clouds .
In this paper we present the results of a search for the transient stellar obscurations such clouds are expected to cause .
We examine the Macho project light curves of 48 \times 10 ^ { 6 } stars toward the Galactic bulge , LMC and SMC for the presence of dark cloud extinction events .
We find no evidence for the existence of a population of dark gas clouds with A _ { V } > 0.2 and masses between \sim 10 ^ { -4 } and 10 ^ { -2 } M _ { \sun } in the Galactic disk or halo .
However , it is possible that such dark cloud populations could exist if they are clustered in regions away from the observed lines of sight .