This scientist's death in the Alaska wilderness was a mystery; 150 years later, his skeleton helped solve it

The last anyone heard of Robert Kennicott was his cheerful hum as he strolled into the Alaska wilderness early on the morning of May 13, 1866.

It was good to hear the scientist sing. It had been a long and punishing winter at Fort Nulato, where Kennicott's expedition to map the Yukon had spent the last five months, and he bore the setbacks badly. The frigid cold and endless dark left no time for exploration or research, a fact that rendered Kennicott "entirely broken down," a friend wrote.

This was not a young man used to failure. By age 30, Kennicott had become an accomplished explorer and celebrated naturalist for the Smithsonian Institution. He was bold, brilliant and fearless; someone who handled venomous snakes with his bare hands.

When Kennicott didn't return, his men began to worry. The expedition's engineer brought up a note their leader left for him that morning, which included instructions "in case of any accident happening to me."

A search party was hastily mobilized; rescuers fanned out across the bleak, mountainous landscape. Soon two of them arrived at the Yukon River, just south of the fort, where their worst fears were confirmed. Kennicott lay on his back on the muddy beach, his arms across his chest, his hat fallen on his face, his body completely still. He was dead.

Tenderly, the devastated men lifted their leader's body and began to carry it back to the fort. That's when they noticed something strange: The small vial of medicinal strychnine that Kennicott always carried with him was missing.

In 1866, whispers traveled faster than ships. By the time Kennicott's remains were returned to his family homestead in Illinois, called the Grove, eight months after his death, the rumor that Kennicott had killed himself with a fatal dose of the poison had already taken hold. What else could explain the death of a man seemingly in his prime of life?

"It was a question only Kennicott could answer," said Stephan Swanson, director of the Grove, which is now a National Historic Landmark. And Kennicott was gone.

But his remains, which had been buried in a cast iron coffin, were incredibly well-preserved. If the man couldn't solve the mystery of his death, perhaps his skeleton could.

Unearthing Kennicott

Today, Kennicott's bones are housed at the Smithsonian's National Museum of Natural History, just one of millions of research specimens the public rarely gets to see. NMNH has the world's largest natural history collection – 145.3 million objects that fill 1.32 million square feet of space.

To find Kennicott amid this vast assemblage, you must walk past the museum's famous elephant, through the throngs of tourists, up several flights of stairs and down a long hallway lined with drawers containing human skeletons, to the office of Kari Bruwelheide and Doug Owsley. They are forensic anthropologists – scientists who specialize in analyzing human remains to decipher how someone lived and died. They've famously assisted efforts to identify those killed in the Waco siege and the 9/11 attacks, as well as Civil War soldiers and early Jamestown inhabitants. And they're two of the world's foremost experts in excavations of cast iron coffins – the kind that Kennicott was buried in.

In the late 1990s, Swanson heard Owsley give a talk at a junior college near the Grove, in Glenview, Illinois. Swanson had idolized Kennicott for decades and was never entirely convinced by the rumors that the naturalist's death was a suicide.

"I thought, here's a Smithsonian scientist" – Kennicott – "who died on the banks of the Yukon River at 30 years old, there's all these theories out there about how he had died. And here's another Smithsonian scientist" – Owsley – "who could figure out the truth," Swanson recalled. "I went up to him after and explained, 'Hey, I have this interesting thing going on.'"

Neither Owsley nor Bruwelheide had heard of Kennicott before this. But their interest was piqued.

Serendipitously, Swanson was already arranging to have Kennicott's remains transferred from a nearby cemetery to the Grove – while the coffin was above ground, perhaps the Smithsonian scientists could take a look. Several years and hundreds of phone calls later, they found themselves inside a barn at the Grove, lifting the heavy lid of Kennicott's iron coffin to reveal the man inside.

"It was truly amazing," Bruwelheide remembered. "You could see his full set of clothing, you could see black, flowing hair, you could see how they prepared the body, all the way down to the socks on his feet that had holes in them, and you knew were the last pair of socks that he ever wore."

Cast iron coffins are sealed with a linseed and lead-based plaster that makes them airtight, and Owsley and Bruwelheide hoped that Kennicott's remains might have been perfectly preserved. But the glass plate on the front of the casket had broken, and the body inside was badly degraded. Adipocere, a grayish, waxy substance that forms from the decomposition of body tissue, pooled beneath the bones.

The scientists still had plenty to work with. Analyzing his hair, they could track deterioration in Kennicott's diet as he left the cushy confines of the Smithsonian Castle, where he lived with other scientists, for the deprivation of the Arctic. Herniations in his spine indicated the weight of the scientific instruments and collecting tools he lugged on his expeditions. Tests of the adipocere revealed traces of mercury, arsenic and strychnine – all of which are deadly.

But it was hard to tell whether the toxins in Kennicott's tissue came from a final, fatal swallow or had accumulated there over decades. Nineteenth-century naturalists frequently used arsenic for killing and storing specimens, and mercury and strychnine were commonly taken in small doses as medicine, a practice that would horrify doctors today.

"The human skeleton, if you know how to read it, you can read it like a book and it can tell you a great deal," Owsley said. "But sometimes it doesn't tell you everything."

The pieces of a life

While Owsley and Bruwelheide puzzled over Kennicott's body, Sandra Schlachtmeyer, a volunteer at NMNH and skilled archivist, pored over the facts of his life.

Journal entries, medical records and thousands of letters revealed the young man born to a well-connected Chicago-area family in 1835, when Illinois was still considered the wild outer edge of the young United States. As a child, Kennicott was often sickly and couldn't attend school, so he got most of his education on the grounds of the Grove, chasing after animals, investigating plants and charting the landscape around his home.

When he was 17, a friend of Kennicott's father introduced him to Spencer Fullerton Baird, who was then the assistant secretary of the newly established Smithsonian Institution.

"Baird recognized his passion and asked him to start contributing specimens to the Smithsonian," Owsley said, "since so many things in Illinois weren't known to Eastern scientists at the time."

Several years later, Baird invited Kennicott to come live at the Smithsonian Castle, which housed a number of other promising young scientists. By day, they studied under the institution's senior researchers, analyzing and cataloging specimens that went into the growing collection. But at night, the men went wild, hosting sack races in the exhibit hall and serenading the secretary's daughters when they were supposed to be asleep. They called themselves the "Megatherium Club" after a genus of extinct ground sloths – a jab at neighbors who complained that their late night high jinks made them sound like "wild beasts."

"Kennicott was a bright and shining light, and no voice was more cheery than his in these gatherings, where all restraint was thrown off after the labors of the day were over," his friends wrote in a eulogy published by Western Monthly magazine in 1870.

He was also – even Owsley almost blushes admitting this – quite handsome: tall and rangy, with thick, dark hair, soulful eyes and a swashbuckling way of carrying himself.

"Everyone says he should be played by Johnny Depp in the movie," he said.

But Kennicott was intensely serious about his work. "In zoology … I mean to do big things," he wrote in a letter to a fellow naturalist. He spent all his summers in Illinois, where he captured and identified thousands of specimens. He helped found the Chicago Academy of Sciences – "the first museum of the West," he liked to boast.

In 1859, Baird asked Kennicott to lead a three-year expedition through British America (now Canada) up to Alaska to document the region's wildlife. He came back with 282 specimens of bird, 230 mammals, 151 fish, plus countless plants, insects and reptiles. He spoke with Native Americans he encountered and documented their languages in his journal, and purchased their clothing, tools and artwork for the museum in the District. By the end of the trip, he had contributed specimens to every division of the Smithsonian. And he was only 27.

The initial Alaska expedition was so successful that Baird recommended Kennicott to lead a second trip, this one for Western Union Telegraph, which hoped to find a route for a telegraph line that would link the United States to Russia beneath the Bering Sea.

The young man's health problems from childhood returned around this time: Letters show he was taking doses of strychnine to stave off headaches and feelings of sluggishness, and he suffered a moment of vertigo while visiting a colleague in Illinois. When he arrived in San Francisco, the last port of call before Alaska, he had a full on attack of syncope – a loss of consciousness due to low blood pressure. His heart had momentarily stopped beating.

By the spring of 1866, Bruwelheide said, "Kennicott was under great stress, he was probably exhausted from the pressure of leading this expedition. He had just suffered an extremely harsh winter where the men had very few supplies remaining and very little to eat. He believed he was not succeeding in the mission as he should have. … You can imagine the circumstances coming together and just taxing his body."

In response, he started taking more strychnine – a dire clue.

"Sandy's research let us put the results of our analysis in context … to figure out what they mean," she concluded. "It all started to come together."

The cause of death

Fifteen years after they first opened his coffin, and 150 years after he died, Bruwelheide and Owsley are finally ready to publish their diagnosis of the cause of Kennicott's death:

"The assembled profile strongly supports death from cardiac arrest," they write in a paper that will be printed in Cambridge University Press this year.

The health complaints described in Kennicott's letters are consistent with Long QT Syndrome, a congenital disease characterized by rapid, chaotic heart beats and fainting spells. Strychnine, which causes muscle convulsions, would have exacerbated the condition. The combination of stress, physical exhaustion and toxic "medicine" was too much for the young scientist's weak heart.

Yes, Kennicott may have poisoned himself. But it wasn't intentional. For Owsley and Bruwelheide, it was almost a relief to come to that conclusion.

"We work many different cases, but without question we've invested more time and effort in this young man than anyone I can think of," Owsley said. "We're scientists, we're always objective," but after all that time spent poring over his letters, immersing themselves in his life, "it is personal."

The anthropologists say they think of Kennicott as a colleague, and their museum is still reaping the benefits of his work. Several years ago, zoologists studying the decline of cricket frogs in Illinois used specimens collected by Kennicott to understand how the creatures have changed between the 19th century and today. The Smithsonian estimates that there are thousands, perhaps tens of thousands of Kennicott-collected objects still in the collection.

"And his contribution goes even farther than what tags read 'Kennicott,'" Bruwelheide noted. He coached many of the young naturalists and explorers who would shape science and the Smithsonian in the second half of the 19th century, including Henry Bannister, whose chronicle of Kennicott's expedition would be used to justify the purchase of Alaska. A glacier, a valley, a river and a town in Alaska all bear the name "Kennicott."

Looking over her notes, Bruwelheide pulled up a heartbroken letter biologist William Dall sent to his sister after learning of his mentor's death. The sheets were wrinkled and yellowed with age, but Dall's immaculate cursive was still easy to read.

"The spur which nerved me to face any danger, and look carelessly on difficulties and trials, by the side of one loved and trusted, is taken away," he wrote. Dall recalled how, just before his death, Kennicott told him that he was glad to have gone on this "unlucky expedition," if only because it allowed them to become friends.

"It was a great comfort to know he had confidence in me," Dall wrote. "I shall try and deserve it."

"This is what draws us to Kennicott," Bruwelheide said, reflecting on Dall's letter. " … He was a great scientist, but an even greater mentor and friend to those who knew him."

As she spoke, Bruwelheide repeatedly glanced toward Kennicott's bones, which have been stained the color of dark leather by the iron coffin that once housed them. Under other circumstances, the human skeleton lying on the table might seem like a prop from a horror movie. But viewed through Bruwelheide's eyes, it's more like a relic of a saint.

Originally, Swanson intended for Kennicott's remains to be reburied at the Grove when Bruwelheide and Owsley's investigation was over. But when the anthropologists realized how important the young man had been to the Smithsonian, they asked if the museum could keep him as part of its 17,000-person-strong human anatomy collection. Swanson brought the request to the modern-day Kennicott family, who agreed.

This year, the bones were formally signed over to the Smithsonian. They're already being used for research on the effects of mercury-based dental fillings and to test the accuracy of facial reconstruction software.

"We think he would like that," Owsley said. "He's a collector who was collected."