Astrance

Water gurgled in the bilges and Phlebitis, doomed sailor, turned his lip up in a faint snarl.  The bilges stank, of dead, fishy things and things that had managed to rot in salt.  The smell was unpleasant, sour in an odd way that he couldn't put his finger on, and probably the third worst thing he'd ever smelled.
The second worst thing he'd ever smelled was boiled frog, and his ship had hauled a cargo of frogs across the Winter Ocean for over six years, boiling the wretched things once they were out of sight of land.  He'd thought that he'd never get the smell of boiled frog out of the wood of the ship, nor that he'd ever forget it.  His nightmares tended to start with the pervasive, vile-green miasma of a freshly boiled frog and usually ended with him waking up in time to vomit over the side of the bed.  His cabin-boy now refused to sleep in his cabin and slept the with the others sailors in a cabin at the other end of the ship instead.
The worst thing he'd ever smelled was Astrance, a spice grown in the tiered gardens of Neuschatsel, that was dried for shipping.  The smell started with the deep, rich tones of fresh fertiliser and went into incontinent dog territory after a second or two, then settled into the higher notes of a three-day old chicken carcass rotting in the sun.  It made vomiting seem pleasant because the acrid notes of bile counteracted the smell quite well, but as the crew had rapidly discovered, there's only so many times you can throw up if you want to have a usable throat.  They were now settling mostly for handkerchiefs dipped in dilute ammonia solution, but Phlebitis found it easier to come down to the bilges three times a day and breathe deeply.
He loathed Astrance more than he loathed boiled frogs, and he'd thought he'd already plumbed the depths of hate that a soul could sink to.
Astrance carried a significant premium with it because there were so few crews willing to transport it, and sea-transport was the only real way to get it anywhere because land-transport could be abandoned by its drivers when they decided that the smell was too much.  Here at sea the choice was between the smell and suicide, and Phlebitis thought that his crew had finally weeded out all those who preferred death.  The price he was being paid to haul it would be trebled when he landed and handed it off to the factors, but the sea-route seemed infinitely long and infinitely miserable.  The only consolation he had was that if the smell permeated his clothes like the boiled frog had it stood a good chance of finally repelling advances from Madame Sosotris when he next visited the Unreal City.
Astrance was mixed, in small quantities by highly trained chefs, with a herb called Fengill that was grown in low, marshy swamplands by the Maigre river.  Done correctly the smell of the spice was modulated into something earthy but wholesome, and the poisons in the Fengill, which could pole-axe an ox in under thirty seconds, were attentuated into something with a tingle and a hint of forbidden sensation.  The whole thing was said to be highly addictive, though possibly lethal if the eater were to get overenthusiastic with the portions, and drove the high prices that those who produced and carried Astrance could demand.
Phlebitis had no desire to try the food, just in case he could still smell the vile odour of the spice just by looking at the food.
Footsteps splashed behind him, and he turned.  The cabin-boy, his face reddened by ammonia burns, looked at him with milky, cataractal eyes.
"Boat ho!" he said, coughing.  His spit was milky too, and bubbled in the bilges, no doubt another side effect of the ammonia.
"What?" said Phlebitis, not believing the cabin boy for a second.  "We're in open water, boy.  There's no boats out here.  Is it a ship?"
"Boat ho!" said the cabin boy.  A thin line of spittle ran out of the corner of his mouth.
"Right," said Phlebitis.  "A boat.  Ho.  Ho-ho-ho."
"And a bottle up your bum!" said the cabin boy, completing the traditional shanty.  Phlebitis rolled his eyes, and headed up to the deck.

*

To his astonishment there was indeed a small rowing boat trying to pull alongside his ship.  The wind was full in his sails and he thought they were probably making forty knots, so that the rowing boat was staying in sight at all struck him as impressive.  He gave the order to spill some of the wind from the sails and slow the ship down, and they let the row-boat catch up to them.  The man sitting in the stern had a face that looked to have been beaten down to a pulp and then resculpted by a golem-maker, and the... thing... rowing had eight arms each more muscular than either of Phlebitis's legs.  It stayed in the boat, slumped over the oars as though tied to them and the man in the stern stood up and waved for a ladder.
A rope ladder was cast over the side of the ship, and the man came up.  He stood on deck, took a deep breath, and promptly ran down the ladder again.
"Hear ye, hear ye!" he yelled from the relative safety of the row-boat.  "Hear now that the trade in Astrance is forbidden on the Angled Isles and the shores of Mostlybony on pain of being buried in the damn stuff.  And don't try telling me you've not got any, that stench is almost strong enough to kill."
Phlebitis leaned over the side of the boat and looked down.  "What do you mean, trade is illegal?" he said.  "Are you saying that possession of Astrance is now illegal in the Angled Isles?"
"Nope, you can own as much as you like," said the man in the boat, sitting down now.  "But you can't buy or sell it.  Or give it away for that matter.  Foul stuff."
"Then what do traders do with it?" asked Phlebitis, trying to stay calm.  "Dump it overboard?"
"No, that's illegal too!" said the man.  "At least in the coastal waters of Mostlybony and the Angled Isles."
Phlebitis swore colourfully, managing three and a half-minutes before he needed to draw breath.  The man in the boat nodded, impressed, and then the thing at the oars sat up and started rowing again.
"Forty-five seconds," said Phlebitis to the crew.  "Then run us over him and cut that damn boat in half.  Making bloody Astrance illegal while we're still carrying the stuff!"