Ellery Queen’s Mystery Magazine. Vol. 100, Nos. 4 & 5. Whole Nos. 603 & 604, October 1992

The delicious aroma of roast pork loin, carved from a wild boar the two Indian men had speared in honor of the occasion, provided a veneer of civilization in the raw hut. But it was abruptly shattered by a hair-raising screech across the broad river.

“Jaguar. Getting ready for the hunt. They hardly ever get over this side.” Durkin said that perfunctorily because he had just realized something that was a lot more disturbing than a jaguar’s evening scream. He had just been struck by the fact that since Kroll had entered the mess hut, his speculative slate-blue gaze had never once wavered from Felicia until the jaguar’s shriek had split the outside silence.

“Breakfast at seven,” Durkin said coldly. “In the lab at seven-thirty. I’ll teach you what I can.”

Kroll was not a morning person, Durkin decided. At breakfast, the man met Durkin’s “Good morning” with no more than a surly nod. In silence, he downed two cups of Agata’s excellent arabica coffee in an apparent effort to jolt himself fully awake. Then he leaned back in his camp chair and stared up at the underside of the thatched roof.

“God,” he muttered in disgust. “There are live things crawling up there.”

“We stay in our part of this little world, they stay in theirs.” Durkin, incorrigibly task-oriented, glanced at his watch. “Time to get to work, Kroll.”

The research building was the best-built structure in the compound. Its corrugated metal roof protected the lab at one end. The rest of the large interior was occupied by rows of bubbling aquariums. The lights here and in the other buildings, the ceaselessly humming aquarium pumps, the laboratory electrical outlets, and the emergency radio in the mess hut were powered by a throbbing gasoline-fueled generator in the adjacent shack. So Durkin informed Kroll as he toured his superfluous assistant through the lab, then into the area of the holding tanks.

“That was the damned thrum-thrum-thrum I heard all night,” Kroll said with a grimace.

“After you’ve been here a while, you won’t notice the generator at all. Now in this first tank—”

“Felicia doesn’t join us for breakfast?”

“Seven’s too early for her.” Durkin tapped his forefinger on the edge of the murky tank to focus Kroll’s wandering attention. “In here is an impressive example of Electrophorus electricus. Notice these two fine wires leading to the volt meter on the side of the tank. The purpose—”

“Wait a minute, Durkin. In English, okay? Electro-for-what?”

“I thought the technical name was self-evident, along with your keen visual observation.”

“Looks like a fat watersnake to me.”

“It’s an Amazon electric eel, capable of a discharge up to five hundred fifty volts. Enough to stun a horse.”

“Why him?”

“I don’t follow you, Kroll.”

“What are you doing with this guy?”

At least that crude question was a flicker of interest.

“I’m tabulating precise measurements of its discharge rates, voltage peaks, and eventually, its controllability.”

Kroll shrugged. “Why?”

“There may be certain medical, even military applications. The latter is classified,” he said with a degree of satisfaction. “Next, we have three tanks of Sphaeroides annulatus.”

“Uh huh. Look like fish to me.”

“They are fish. Not native here, they’re west coast Gulf puffers. Saltwater fish, but the foundation has no facility in that area, so they’re here. The flesh is edible, even delicious. But the intestines, liver, gonads, and skin contain tetrodotoxin, a deadly poison.” Durkin was in lecture mode now, a status he enjoyed. “The victim first notices tingling of the lips and tongue. That develops into numbness of the entire body, respiratory difficulty, hemorrhages of the skin, muscle twitches, tremors, then convulsions. There’s no antidote and only a forty percent survival rate. The foundation is interested in the puffer’s pharmacological possibilities.”

“Swell,” was all Kroll had to say.

They moved on to an outsized tank of brownish water that seemed paved with large, fleshy discs.

“Stingrays,” Kroll offered, apparently unimpressed by a creature so commonplace.

“Potamotrygon motoro, the Amazon variety of freshwater stingray. The venomous stinging barb on this variety is situated well out on the tail instead of at its base.”

“So?”

“So that weapon near the end of the long whip of a tail makes the Potamotrygon among the most dangerous of the species. The wound is hugely painful, of course, and stings in the upper-body areas have been known to be fatal. Again, there is no specific antivenin.”

Kroll bent to peer into the tank, shrugged, and straightened. Durkin waited for his obvious question, but he said nothing.

“The purpose of the rays’ being here is the simple extraction of venom for shipment to a Miami research lab in search of an antidote.”

Sweat began to stain Kroll’s shirt, not from the impact of this little hall of aquatic terrors, Durkin surmised, but from the oppressive humidity.