I woke to find a fish chalked on the asphalt.
   It bled a bit, in the first of the autumn rains,
and then was gone, mere inchling. Water erased it,
   one more idea lost to fugitive sensation.

So I lay a while and thought of the garum factory
   the Romans built once on the Numidian coast,
sunk now to airy vats and broken masonry,
   but the sauce of simmered fish guts it produced.

violently salt and dark with the heat of the sun,
   was bottled in tall, narrow-waisted amphorae
for export, the ancient equivalent of A-1.
   What's more, according to the OED,

Tobias Smollett knew it as saltfish water:
   a pound of olive oil mixed with the blood and gills
of the tunny and applied at the whimsy of an ostler
   to the left nostril of an ailing mule;