Boris Krukoff appeared as though he might vanish at any moment, his frame perilously slender and his eyes disproportionately large as they bulged from deep sockets. By the moment he joined the American pharmaceutical giant Merck, he was already becoming one of the foremost plant hunters roaming the tropics. He learned when to rely on his own abilities and when to summon others to finish a job or extricate himself from danger. He also knew when to keep things hidden—especially plant specimens—away from prying eyes, be they customs inspectors, rival explorers, or competing interests. These traits proved advantageous for a field botanist navigating the international plant and drug trade. Krukoff proved to be Merck’s ideal pick for the company’s plant division in the Amazon, and soon enough its curare specialist in practice as well.
Born in central Russia in 1898, Krukoff spent his formative years in the modest town of Kosmodemiansk, perched along the Volga. His father worked as a botanist, and it is likely he sparked the boy’s fascination with collecting specimens. Krukoff studied at the local gymnasium—a fusion of primary and secondary schooling—and graduated with honors in the spring of 1917. During his final years there, he summers worked for the supervisor of Kosmodemiansk’s National Forest, a glimpse into a vocation that would carry him through forests around the world. After finishing school, he spent four months training at Moscow’s Alexander Military Academy, serving briefly in the 95th Infantry Regiment. He soon left the military, returned home, and moved further down the Volga to Kazan, where he enrolled at its university to study law.
Very soon, the upheaval of the Russian Revolution and civil war overturned his life. While at the military academy in Moscow, the unrest of the “July Days”—a week of armed demonstrations against the provisional government in Petrograd (St. Petersburg)—foreshadowed the violence that would accompany the Bolshevik takeover. For the next five years, Krukoff’s path zigzagged across Russia, further from his Volga hometown and his woodland rambles.
In 1918, amid the early days of the revolution, Krukoff reengaged with military service. He fought against the Bolsheviks as part of the White Army and later within the White Navy and Marines. His assignments included reconnaissance missions that involved slipping behind enemy lines to report on the Red Army’s Volga flotilla. These dangerous tasks culminated in his capture in 1919 and a period as a prisoner of war. He escaped from POW camps multiple times, at one point being pressed into Red Army service as a suspected deserter. The Reds sent him to the front with thousands of conscripts, most without weapons. He ultimately managed a final escape, crossing back into White-controlled territory and venturing deep into Siberia to rejoin the Russian Admiralty at Omsk. After further mobilizations and combat, he joined the White Navy and its Siberian flotilla in Vladivostok on the Pacific coast.
For a botanical hired gun like Krukoff, secrecy was next to godliness.
Krukoff chronicled his epic with painstaking care. He had begun this habit as a boy—“An accurate record of my hunting from 1913 to 1918 inclusive”; “My observations of spring 1912 to 1917 in Kosmodemiansk”—and he would carry it forward on every long plant-collecting expedition. He was “a man addicted to organization,” a contemporary remembered. The records reveal forged passports, a prison-barge escape by leaping from ship to ship, and dodging “Red Magyars and Chinese troops” while crossing front lines. He learned how to assemble data of many kinds. His White Navy service concluded after the defeated fleet found refuge in the Philippines; when US authorities granted passages to fellow sailors and officers to San Francisco, Krukoff slipped away once again, seeking a land of his choosing. He worked for a time on a plantation in central Luzon, where his first exposure to tropical flora occurred, but soon left for Australia, which he disliked “because of the Labor Government.” He then wandered to Canada, which he also disliked for placing him in the French-speaking portion of the country. Eventually, it seems, he found his lane in the United States. “I liked New York.”
Krukoff arrived at Ellis Island on March 29, 1925. The city’s rhythm surged across the Hudson as it did during the prosperous 1920s, and on the Upper West Side, the American Museum of Natural History showed the fossilized bones of a mastodon recently uncovered during apartment-building excavations. The museum even offered a ten-dollar reward for the discovery of missing teeth, a gesture amid the fog of spring when Lower Manhattan still wore the smoke of a fire that had displaced many in the immigrant neighborhood known as the “neighborhood of all nations.”
Though New York was preferable to French Canada, life as a single immigrant with limited English, no kin, and little money proved strenuous. He spent the summer taking odd jobs in Manhattan, often juggling two at once. His days blurred into long shifts, hurried meals, and halting conversations in a language he barely understood. He combined day jobs painting and bricklaying with a night shift as a private security guard. Between rounds he practiced English at Evening Elementary School #103 in Manhattan. The schedule left little time for sleep, and during a stint as a night watchman at a garment factory he dozed on stacks of freshly arrived garb between rounds. Yet he saved relentlessly; by fall, he had accumulated enough money and mastery of English to enroll at the New York State College of Forestry in Syracuse. After three years of intense study, he graduated cum laude.
With a résumé that read like a fantastical blend of U.S.-trained forester, seasoned traveler, and former clandestine operative, Krukoff began his job search. The Great Depression had not fully arrived, but the 1920s were no longer roaring. “Next to impossible to get a job,” he later said. His tactic for landing employment mirrored his method for plant hunting: a targeted strike backed by overwhelming effort. He believed his best odds lay with “some American concern, preferably planting rubber in the tropics.” As part of his campaign, he dispatched three letters to different branches of a U.S. rubber firm, Intercontinental Rubber, including one to a little-known Mexican affiliate.
All three found their way onto the desk of the company’s president, G. H. Carnahan, headquartered in New York City. Carnahan—an affluent, Harvard-educated engineer and inventor who had risen through Intercontinental Rubber’s ranks—had patented techniques for processing ore at Chilean nitrate mines and for extracting latex from the guayule plant, a shrub native to the U.S. Southwest and Mexico that supplied a significant portion of the North American rubber market. Impressed by Krukoff’s tenacity, Carnahan invited him for an initial interview at his Manhattan office. The encounter confirmed Krukoff’s suspicions: he was driven, thorough, and relentless.
Carnahan assigned him a provisional task. He sought to test a different venture: a proposed method for shelling the hard-shelled babassu nuts, which were valuable for oil and cooking. If the new process worked, it promised substantial profits since German buyers consumed margarine produced from these nuts. To evaluate its feasibility, Carnahan wanted someone on the ground in Brazil. He asked Krukoff to go there and verify the plan’s viability. It was a test designed to gauge his nerve as a field operative.
Neither man realized it at the time, but that assignment would pull Krukoff into a lasting fixation with the Amazon’s flora and remedies, the realm of economic botany, and, before long, the notorious Flying Death.
*
Krukoff sailed away immediately after completing forestry school. For the next ten years, he spent more time on plant-collecting and other economic botany missions than he did in the United States. On the babassu project alone, he endured six months of travel through northeastern Brazil, crisscrossing Pará, Maranhão, and Piauí. He turned his meticulous data gathering into a weapon: catalogs of field sites, yields, wholesale prices, and likely competitors. By the end of the year, he believed his ledger of information was adequate to satisfy his master. He left the Brazilian heat and returned to New York in January 1929, his mind already cooling into a plan.
He went straight to Carnahan at Intercontinental Rubber and presented his comprehensive report. Krukoff warned that the venture would prove unprofitable, in part because others had overstated the nut’s supply and geographic reach. Several firms had rushed in, lured by the prospect of massive profits, only to withdraw when they learned the real Brazilian conditions. The moment to back out was now; he urged Carnahan to stay away.
Krukoff’s conclusions drew on his growing botanical expertise and his exhaustive on-the-ground surveys, blended with a sober assessment of supply chains and markets. His cautious memo fortified his bond with Carnahan and the rubber investors’ circle. He later recalled that the analysis “made me.”
As a reward, Carnahan sent him back south. Merely two weeks after reaching New York, Krukoff found himself boarding another steamer bound for Brazil’s Pará state to survey additional babassu and seed-oil opportunities near the Amazon’s mouth. The pattern continued for years as he was dispatched by Intercontinental Rubber and allied firms to explore wild flora, plantations, and business prospects across the globe. After returning from Pará, he swung to California to assess guayule rubber production, and then went to Chile and Spain to scout guayule cultivation sites. He also revisited traditional rubber plantations in Sumatra, controlled by Intercontinental subsidiaries, and returned to the Amazon on subsequent trips. His network with Carnahan opened doors to further assignments, including his first trip to Africa when he was “loaned” to the Insular Lumber Company of Philadelphia to study varieties of mahogany in a case involving trade-name disputes. These early journeys deepened his tropical botany knowledge, perfected his specimen-collecting technique, and sharpened his leadership skills as an expedition organizer. He also fell in love with tropical flora, especially Amazonian vines and flowering trees, which became his botanical specialty and lifelong obsession. His other specialty was strategic: he combined botanical science with commercial opportunity, chasing multiple scientific goals and revenue streams on each mission, always seeking to maximize profits from his research. He honed this model on his third expedition to the Brazilian Amazon.
When he set sail for Brazil in August 1931, the Gills were refining their Río Negro estate in Ecuador, and the Great Depression was wreaking havoc across the Americas. Governments across Latin America teetered, while populist leaders promised economic independence. In Brazil, Getúlio Vargas held the reins, advancing a nationalist program after a calamitous year for coffee prices. Back in the United States, over one-fifth of workers were unemployed. Krukoff, by contrast, had secured three different lines of work: first, the collection of plant samples to be sold to scientific institutions and herbariums in the United States and beyond; second, ethnobotanical research on Indigenous fish poisons and medicinal plants for a U.S. company, with an eye toward their commercial value back home; and third, espionage on Henry Ford’s rubber empire.
By this point Krukoff had established a working relationship with the New York Botanical Garden, a preeminent hub for herbarium work and botanical research. The Bronx institution collaborated with him to name and distribute his plant samples, keeping copies for its own archives. This line of work, combined with his commission to explore medicinal plants, provided perfect cover for a hidden objective: spying on Henry Ford’s vast rubber concession—the Companhia Ford Industrial do Brasil, colloquially known as Fordlandia, a settlement approaching the size of Rhode Island and located near the Tapajós River. Ford’s goal was to secure his own rubber supply and to project an image of disciplined labor relations in the Amazon.
Krukoff scoured the Fordlandia grounds for weeks, and only one person appeared suspicious enough to speculate on his true assignment. Passing as a merely curious botanist, he compiled a seventy-four-page dossier—labeled “Short Notes”—that detailed the inner workings of Fordlandia with the gusto of a noir sleuth. He described the personalities and capabilities of expatriate managers (for example, “Although he is rather provincial and is not broadminded, he has a very good head”; “Mr. Davies, an Englishman of middle age, without a personality, suffering from inferiority complex, and unhappy marriage”) and the labor relations with Brazilian workers (“I have been told by several people that the [labor] riot was a well organized affair, none of the Americans knew anything about it”; “On the porch are located two ‘punch clocks’ which, in my judgment, are largely responsible for the last riot”), as well as the challenges of growing rubber in the Americas (“it is very unlikely that in the next 10-12 years they will be able to produce rubber as cheaply as the Oriental plantations”). He concluded, with uncanny foresight, that the plantation model for rubber cultivation faced enormous obstacles in the Amazon, despite Ford’s massive financial commitments.
Krukoff ran his investigations and business ventures with the same intensity and at a pace that punished his body, yet he rarely complained. He thrived under demanding circumstances and enjoyed boasting about collecting specimens in places where other botanists would not dare go. He prepared for his Fordlandia assignment by collecting in the most remote reaches of the central Amazon, a corridor between the Tapajós and Xingu rivers. Reaching his field sites from the Tapajós required more than a week: two days in an outboard canoe, a day of paddling on human power, and another four days on muleback when waters fell too shallow. The specimens he gathered on those early forays were of such superb quality that the New York Botanical Garden swiftly moved to acquire them for its valuable herbarium collections in the United States and Europe. His specimen sheets—carefully preserved samples and precise locality data—found homes in major institutions around Berlin, Geneva, Paris, London, Stockholm, and Utrecht, as well as the leading gardens in the United States.
Krukoff saw no conflict between his scientific research… and the economic possibilities that came with it.
In a later expedition financed by Merck, Krukoff traveled to Bolivia to locate Cinchona seeds—the source trees for quinine, the antimalarial cornerstone. He worked alongside the esteemed Brazilian plant collector and Amazon explorer Ricardo de Lemos Fróes, and the two lived for weeks in a remote camp away from suspicious eyes. It was a rough base, but perfectly suited for cinchona collection. After weeks of tree-hunting in the surrounding forest, Krukoff and Fróes found themselves cut off from fresh provisions. They survived by hunting bushmeat, gathering forest fruits, and rationing dry goods. While they obtained an enormous quantity of seeds with high yield, they also contracted a brutal case of scurvy that nearly cost Krukoff his teeth.
Like his other missions, the Bolivian cinchona undertaking for Merck was suffused with secrecy, reconnaissance, and behind-the-scenes deals. On their return to La Paz, Krukoff and Fróes kept portions of their operation quiet. The project fed into a broader U.S. government initiative to secure Cinchona and quinine sources in the Western Hemisphere, making it illegal to export seeds from Bolivia. If caught smuggling, Krukoff faced prison time, so he split the payload into three batches sent by different routes: one by air express northward, another concealed within plant specimens, and a third entrusted to the American Consulate in La Paz to be shipped back with diplomatic mail. Once the seeds were gathered and reassembled in the United States, they were distributed to “cooperators” (subcontracted growers) involved in the cinchona program.
He hadn’t planned to fall short on vitamin C, but he did prepare for the possibility of keeping his work clandestine. In his field kit he carried a pocket edition of Bentley’s Phrase Codes, a manual for encoding messages. Before departure, he informed a Merck contact that he would append instructions to the manual so Merck could decode any specialized terminology. The manual already contained entries for “seed(s)” (the base cipher was “pynso”) and for “Can sell” (“pyzab”), but nothing for plant cuttings, cinchona, or scurvy. He would have to improvise on those terms. Economic botany was a different kind of conflict, yet it reminded him of his days performing reconnaissance during the Russian civil war when he sent messages across front lines. For a botanical mercenary like Krukoff, discretion was practically sacred.
Krukoff was an extreme stoic, sometimes to a fault. In later years, he missed his wife’s funeral—friends said he was “devoted to [and] dependent on” her for decades and feared showing “unmanly emotions.” Quick-tempered and sometimes brusque, he had little tolerance for fools. He could be rude and blunt, barking orders to assistants only to fill the air with a stuttering catchphrase, “heeyum, heeyum, yum,” as he pinned down his next demand. If he suspected someone of impeding his research, he would blacklist that individual on a personal level. He also preferred to avoid having his picture taken, only giving in when a passport or visa required it.
Yet he possessed a few soft points. When Krukoff’s autocratic demeanor grew too pronounced, a trusted colleague recalled that “his crusty exterior could be pierced by a sharp rebuke to his pride.” After a moment of sputtering, he would break into a boyish, apologetic laugh that briefly softened his stern facade.
Krukoff perceived no internal conflict between the rigors of scientific research—the discipline of collecting, classifying, and analyzing plant specimens—and the economic opportunities his work could bring. He viewed the two as a potent, mutually reinforcing combination.
In 1932, Krukoff crystallized his dual approach. He formed a business venture with his original patron Carnahan and a third partner, G. W. Cole. Cole was a Wall Street financier whose firm had backed Krukoff’s ethnobotanical work during the Fordlandia expedition. Along with Carnahan, they shared a common aim: to extract value from the forests of “Tropical America.”
They dubbed their effort a “syndicate.”
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Excerpted from The Flying Death: Poison, Plunder, and the Quest for a Miracle Medicine in the Amazon by Matt O’Hara. Published by Farrar, Straus and Giroux. Copyright © 2026 by Matt O’Hara. All rights reserved.
