During the French Revolution, a botanist's letter asking about "dear Rhus" (poison ivy) was intercepted, leading authorities to suspect he was conspiring with the Russians.

During the French Revolution, a botanist's letter asking about "dear Rhus" (poison ivy) was intercepted, leading authorities to suspect he was conspiring with the Russians.

During the French Revolution, a botanist's letter asking about "dear Rhus" (poison ivy) was intercepted and led to authorities' suspicions he was conspiring with the Russians

The 1794 incident involved André-Ignace-Joseph Dufresnoy, a French army physician researching the plants' potential medicinal properties. Rhus radicans is a scientific name for the plant, though it's commonly called Toxicodendron radicans.

Poison ivy was sent to Europe in the 1600s as an exotic, ornamental oddity, where it was purposefully grown in the English royal gardens at Kew, the Faculty of Medicine in Paris, and a few other locations.

Poison ivy was sent to Europe in the 1600s as an exotic, ornamental oddity

The plants were grown in the English royal gardens at Kew, the Faculty of Medicine in Paris, and a few other locations.

'The Republic of Letters' was an analog internet for the Enlightenment.

The virtual intellectual society exchanged tens of thousands of letters and spanned several continents. Some of its most avid correspondents were Voltaire, Benjamin Franklin, and Saint Ignatius of Loyola, founder of the Jesuits.

Poison ivy's characteristic rash is caused by an allergic response to an oily compound in the plant called urushiol.

The expedition documented 240 plant species, 178 new to western science

Lewis and Clark’s botanical records introduced species to Americans like bitterroot, ponderosa pine, and Oregon grape—plants unknown to western science at the time. See a selection of these species in this image gallery.

In 1910, riots swept Champagne over unfairness in the winemaking industry

The French are well known for protesting, and their winegrowers are no exception. After years of disastrous harvests caused by bad weather, disease, and deceptive practices by large Champagne houses, smaller vintners fought back.

'Roses are red, violets are blue' has a long, twisting history

The earliest known use of the phrase, a stock romance form used in greeting cards, is in Edmund Spenser's "The Faery Queen" from 1590 (excerpt below). By 1785, Joseph Ritson updated the verse and connected it to Valentine's Day, creating a cliché that's still used today.

Leprosy has been detected in British red squirrels

The animals have been infected with both strains of the bacterium that cause leprosy. Researchers have found that squirrels living in different parts of the UK were infected with different species of the disease-causing bacteria. (Some users may experience a paywall.)

Cannes' Sainte-Marguerite was home to the 'Man in the Iron Mask'

Although his identity was never known, the man imprisoned under King Louis XIV and forced to wear a mask—reputedly made of iron, though likely to be velvet—was imprisoned on an island off the coast of Cannes.

A French Army surgeon discovered that malaria is a parasitic disease in 1880—but scientists were initially skeptical

Charles Louis Alphonse Laveran won the Nobel Prize for his work "on the role played by protozoa" in causing diseases. His work included discovering and reporting the malaria-causing parasite in the blood of a patient suffering from malaria.

Key was initially opposed to the War of 1812

Like the majority of Americans, Francis Scott Key was opposed to the US declaring war on Great Britain, calling the move “abominable.” His feelings began to change after the British raided Washington, D.C. He joined the Georgetown Artillery shortly after.

The FBI investigated John Steinbeck, believing he might be a communist.

Benjamin Franklin once wrote a satirical essay about passing gas

The Founding Father was asked to judge a contest for the Royal Academy of Brussels, but was incensed by one of the contest's questions, which he believed was highly impractical. In response, he wrote a piece suggesting that the most essential problem for scientists to solve was the "fetid Smell" that came with passing gas.

Sir Thomas Overbury's poem "A Wife" inspired its subject to poison him

Overbury wrote the critical poem to suggest that the ex-wife of his friend Robert Carr, Frances Howard, had failed in her marital duties. Its contents enraged her, leading her to craft a conspiracy that left Overbury dead from poisoning.

How slugs helped soldiers during WWI

Slimy, squishy, slow-moving, and heroic? Slugs are land-dwelling mollusks known mostly for causing havoc in our gardens. But during World War I, slugs saved numerous soldier's lives as poison gas detectors. Learn how the unpleasant creatures earned their stripes in the battle to protect soldiers from chlorine, phosgene, and mustard gas as organic detectors.

Paul Revere rode to Concord to warn rebel leaders of British attack

Revere was a well-known Boston messenger and an excellent horseman, known as a reliable relayer of messages. As Boston’s patriot leaders spread out into the areas around the city in fear of British arrest, Revere turned his skills to aid the revolutionary moment.

'Johnny Appleseed' was the itinerant horticulturalist John Chapman

Born in 1774 in Massachusetts, Chapman planted apple orchards for pioneers across Pennsylvania, Ohio, and Indiana, to be sold to locals to produce hard cider. He became famous through a 'Harper's Weekly' profile in the late 1800s, cultivating the modern legend.

The research pipelines being explored by the RIPE Project to improve photosynthesis

These include engineering plants with faster stomata, which would allow photosynthesis to resume more quickly amid fluctuations in available light due to clouds or shading from other plants, and resolving bottlenecks in the regeneration of RuBP, the molecule to which carbon dioxide is fixed during photosynthesis to initiate the Calvin cycle. (Some readers may experience a paywall.)

When a Paris department store hesitated to sell Estée Lauder's perfume, she 'accidentally' broke a bottle, causing the smell to spread throughout the store and shoppers to start asking to buy the scent.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

The Ruggieri family of pyrotechnicians innovated on European fireworks displays

The Ruggieri family transformed fireworks from military to theatrical displays by focusing on artistry. Claude Ruggieri's knowledge of chemistry allowed him to produce vivid green fireworks, a first in Europe.

Revisiting the ornamental hermit craze of the 1700s

One of the more elaborate gardening trends of the 18th century was the placement of a well-designed hermitage within the landscape, a throwback to the more religious antiquity and the Middle Ages. The trend went so far for some that they hired real live hermits, preferably older, bearded, and willing to stay quiet and out of the way. Read about the wild trend here.

Rachel Carson didn't argue for wholly organic farming

Her 1962 book, “Silent Spring,” inspired many people to consider the chemicals used to grow their food, but Carson didn’t think that manufactured fertilizers needed to be banned from farming, writing that “The ultimate answer is to use less toxic chemicals so that the public hazard from their misuse is greatly reduced.” When she testified to Congress in 1963, she said, “I think chemicals do have a place.”

'Brave New World' author Aldous Huxley turned to LSD on his deathbed

As "Brave New World" author Aldous Huxley lay dying of cancer in 1963, he asked his wife Laura to dose him with the hallucinogen LSD. A month later, Laura Huxley wrote a letter detailing the author's final trip, which she notes ended "so slowly, so gently, like a piece of music just finishing in a sempre piu piano dolcemente."

Who was Maximilien Robespierre, leader of the Reign of Terror?

This 28-minute podcast details the life and death of French revolutionary Maximilien Robespierre, who was killed by the people he previously led in 1794. Robespierre is considered the leader of the Revolution's Reign of Terror, a period of intense...

How royal panic led to Europe's deadliest witch hunts

This article delves into the witch "panics" and hunts that roiled across Scotland between 1590 and 1662. The witch hunts in Scotland were unusually deadly, with the country having five times the average European execution rate per capita. Their...

See which Russian Revolution faction your politics most closely match

This quiz asks about property rights, women’s suffrage, and church–state separation to reveal whether your views align most with the Bolsheviks, Mensheviks, Anarchists, or the ultra-nationalist Black Hundreds.

Many legends about George Washington, including his supposed wooden teeth and the story of cutting down the cherry tree, lack evidence.

Harvard drowned rats for this?

Harvard's 1950s rat study was ethically questionable, but scientifically profound. One rescue attempt made rats swim 40x longer. The finding: hope isn't poetic, it's biological.

In 1915, workers recovered a submarine-like vessel from the Chicago River, prompting fears of German espionage

US intelligence allegedly pursued more than 600 schemes to assassinate Cuban revolutionary Fidel Castro.

Famed poet TS Eliot rejected the manuscript for George Orwell's political fable 'Animal Farm,' writing that its criticism of authoritarianism was not 'the right point of view.'

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

After the Boston Tea Party, colonists switched to coffee, which became the main morning drink for revolutionaries.

Before writing 'Walden,' transcendentalist Henry David Thoreau nearly burned down his hometown with a campfire that grew out of control.

The 19th-century painters of the Hudson River School were among the first American romantics, with portraits that displayed the natural beauty of the young country.

Abraham Lincoln was almost assassinated weeks before his inauguration as he traveled from Illinois to DC through Baltimore in 1861; it took two independent claims for Lincoln to be convinced the threat was real

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

The rivalry between Alexander Hamilton and Thomas Jefferson centered on federalism—the question of how much power the federal government should hold relative to the states.

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

How the most famous Ebola book, The Hot Zone, which sold 3.5 million copies and was translated into 30 languages, got aspects of the disease so wrong.

The term 'algorithm' originated from the Latinized name of al-Khwārizmī, a 9th-century mathematician whose works introduced Arabic numerals and the decimal-based numeral system to Europe and whose treatise 'Al-Jabr' gave algebra its name.

In 2018, 26-year-old missionary John Allen Chau was killed by tribesmen after attempting to reach and evangelize on India's isolated North Sentinel Island

Prince's sexually explicit 1984 track 'Darling Nikki' attracted the ire of the Parents Music Resource Center, an advocacy group that inspired the Parental Advisory sticker, even though the song ends with a Christian message.

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

Hotels in Cannes, the glamorous city on the French Riviera, hire hawks to ward off seagulls during the city's famous film festival.