I learned it as:

Ohhhhhhhhhh, the liquor was spilled on the barroom floor
and the cat was out for the night,
whennnnnnnnnn a little brown mouse crawled out of his hole
and sat in the pale moon light.

Heeeeeee lapped up the liquor on the barroom floor
then back on his haunches he sat.
And all night long you could hear him roarrrrrr,
"Bring on the god damned cat!"