by What Linnaeus Saw- A Scientist's Quest to Name Every Living Thing (retail) (epub)
Then there was the goose-barnacle. People who had never seen geese breeding in coastal European habitats believed that these barnacles “nested” on coastal tree branches and then fell into the ocean where they gave birth to geese. Linnaeus explained that barnacles were actually shelled sea creatures which attached themselves to driftwood floating near shore. Their feathery appendages filtered the incoming tide for food. Barnacles hatched barnacles, and geese had geese for parents.
On quiet summer nights, people stared at their ceilings and worried about the tick-tick-ticking of the deathwatch beetle in the rafters and walls. They thought this creature kept vigil over someone about to die. While Linnaeus did believe in ghosts and omens, he attributed the ticking to the fact that the beetle burrowed in wood. We now know that the beetle makes this sound by bumping its head against the wood. Why does it do that? To attract a mate. Later, its larvae hungrily bore tunnels through the rafters.
Despite the occasional deathwatch beetle, homes were people’s safe havens. Beyond their villages, a scary world of unknowns lay in wait. Oceans upon oceans ended who knew where. Their watery depths contained who knew what.
Norwegian sailors, American whalers, and seamen from every country returned from years-long voyages with bone-chilling stories of sea monsters that swallowed boats whole. The Norwegians called them kraken. They said that a single kraken with its long tentacles could take down a sailing vessel and all souls on board. The reports probably described giant squid, which we now know can be nearly sixty feet long and weigh two thousand pounds. Linnaeus eventually classified this real animal as a cephalopod, a member of the same group as octopus, squid, and cuttlefish.
Published in Buffon’s encyclopedia, this drawing of a “kraken octopus” by French naturalist Pierre Denys de Montfort was inspired by a 26-foot-long tentacle found in the mouth of a sperm whale in 1783.
Other animals that Linnaeus added to his list of questionable creatures included:
Antilope, a deerlike animal with twirled horns (it was real);
Lamia, a Greek demon that sucked the blood of children (not real);
Manticore, or man-eater, with a lion’s body, human head, three rows of sharklike teeth, and a tail that could shoot poisonous spines (not real);
Last was the siren, which was part-bird, part-woman. This creature’s song was said to cause shipwrecks by luring sailors toward dangerous rocks. Strangely, Linnaeus was unsure about this one. Both he and his friend Peter Artedi seriously considered the existence of sirens and mermaids. Eventually Linnaeus, who had never seen one either dead or alive, speculated that the reports were mistaken sightings of manatees, dolphins, or seals.
Linnaeus eventually dropped the category “Paradoxa,” perhaps assuming that he had put an end to the false myths.
Owners of curiosity cabinets also began to turn their focus away from fabulous impostors toward real plants and animals. Wealthy collectors now wanted their collections to be scientifically authentic. Some hired trained naturalists to improve their collections and to create accurate labels and catalogs. Over the years, Linnaeus would be hired to slay fake “dragons” and organize the shells, flowers, minerals, and animals in many extensive collections, including those of the Swedish king and queen.
After his abrupt departure from Germany, Linnaeus arrived in Holland at the University of Harderwijk, armed with a brief thesis on malaria. He had written it back in Uppsala, where people often contracted and sometimes died from this fever when Uppsala’s humid summer weather descended along the swampy river Fyris. In the thesis, he incorrectly blamed the sickness on particles of clay in drinking water. Scientists would not know until the end of the nineteenth century that the real cause was a parasite spread through mosquito bites. However, Linnaeus apparently presented a convincing argument. He defended his thesis before the faculty at the Dutch university and on June 24, 1735, six days after arriving, he received his medical degree.
Now open for business, Linnaeus found both his botanical and medical services in demand in Holland.
5
CAN BANANAS GROW IN HOLLAND?
Dawn was always a friend of the muses.
—CARL LINNAEUS, LETTER TO JOHANNES BURMAN, JANUARY 1736
As a young, new doctor in June 1735, Carl Linnaeus was short on money but loaded with ambition. He traveled from Harderwijk to Amsterdam, a city of leisure and elegance, of silk clothes and foods with foreign tastes and strange aromas imported from distant places. Crucially, to Linnaeus, the city was a hub of scientific activity. He rushed around introducing himself to leading scientists and hustling his revolutionary ideas about how to reorganize the natural world. Ever since he and Peter Artedi had divided up the task of classifying the natural world during their student days at Uppsala, Linnaeus had been steadily organizing and refining his system. By the time he arrived in Amsterdam, he was ready to publish his ideas—but first, he needed a job.
Linnaeus had a strong personality and sky-high self-confidence and often left a bad first impression. Despite this, most people were won over by his intelligence and irrepressible charm on meeting him a second time. Now with medical degree in hand, he was in a hurry to launch his career and return to Sweden to marry Sara Lisa.
In Amsterdam, Linnaeus found he could trade his botanical expertise for a room and meals with Johannes Burman, director of the city’s botanical garden.
Twenty miles away, Burman’s friend George Clifford lived in luxury on his country estate, Hartekamp. Clifford was enormously wealthy. Heir to a banking dynasty, he was a director of a powerful commercial empire, the Dutch East India Company. This century-old business had a trading monopoly on imports from the lands around the Indian Ocean. Clifford, a botanical collector, could get anything he wanted from anywhere in the world. His sea captains kept the gardeners on his estate busy unpacking crates of exotic plants and animals.
One day, Clifford invited Burman and his Swedish house-guest to tour his magnificent estate. The garden was a living catalog of nature’s diversity. Only a privileged few had ever seen it. The estate was like “paradise,” according to Linnaeus. The private zoo was alive with wildness—the roaring, growling, grunting, and howling of tigers, monkeys, antelopes, and warthogs. In the aviary, Linnaeus spotted pheasants, American falcons, teals, sandpipers, swans, coots, buntings, African grey parrots, crossbills—so many birds, he said, that the garden echoed and re-echoed with their calls.
As they walked the shaded paths and man-made hills, they passed statues and mazes, topiary shrubs carved and snipped into artistic shapes. Flowerbeds splashed color everywhere.
Then they came to four buildings with large windows. These greenhouses were called orangeries by the French because they protected citrus trees and other cold-sensitive plants from freezing in the northern climate.
In the first grew southern European plants; in the second, Asian plants; in the third, African plants; and in the fourth, strange species from the New World. Some Linnaeus had read about, but most he’d never seen. What he saw in that last greenhouse hypnotized him.
Enormous green bladelike leaves reached for the ceiling, stretching high above New World magnolias, sassafras, cacti, and orchids. No flowers, no fruit; the plant was all leaves, wrapping tightly around each other at their base, fusing together to form a column that looked like a tree trunk. From the column’s center, new leaves rose and unfurled.
Even though the plant had no fruit, he knew immediately that it was a banana plant. In Europe, only royalty and the richest citizens had ever seen a banana, let alone tasted one. They called it a pisang, a word borrowed from a Javanese language.
Linnaeus wondered whether Clifford’s tropical plant could actually bear bananas in Holland. Only three gardens in Europe—one in Austria and two in Germany—had ever managed to produce the fruit. Dutch gardeners, famous for their skill and the highly profitable tulip trade, had never produced a banana. Even the famous botanist Antoine de Jussieu had tried at the royal garden in Paris and failed.
Odds were that the specimen in Clifford’s greenhouse would not do any better. Still, the challenge excited Linnaeus. This could be a dramatic test of his botanical mastery, a way to prove himself. In addition, since affluent Europeans craved expensive imports like tea, coffee, silk, spices, and cacao for chocolate, he wondered whether those imports could be grown in Europe. Perhaps this greenhouse, with its banana plant, would be a good place to start investigating the question.
Clifford was impressed by Linnaeus and offered him a job. For a thousand guilders a year, plus free room and board and access to Clifford’s carriage and extensive contacts, he would serve as the wealthy man’s live-in physician. At fifty, Clifford was worried about his health. Like a hothouse plant, he would require constant care. More compelling to Linnaeus, though, was that in this position he would also curate the gardens, supervise the greenhouses, and reorganize the herbarium, Clifford’s collection of dried specimens.
There was one problem: Linnaeus had already promised to help Burman prepare a book on plants. The thought of losing his botanical adviser upset Burman. Luckily, in Clifford’s library, Burman spotted a rare book that he’d never seen before—volume two of Sir Hans Sloane’s A Voyage to the Islands of Madera, Barbadoes, Nieves, St. Christopher’s and Jamaica. Clifford owned two copies and suggested a swap. Linnaeus was traded for a book!
A month later, on September 13, 1735, the young doctor moved in. Promising to stay the winter, he remained for more than two years. With his usual abundance of enthusiasm, he began to describe all the plants at Hartekamp and worked for a month with Georg Dionysus Ehret, an extraordinary botanical artist who made paintings of the plants. He also dug into the greenhouse work with Clifford’s talented German-born gardener, Dietrich Nietzel.
MEASURING TEMPERATURE
During the first half of the eighteenth century, many people were experimenting with thermometers. Most put a drop of mercury, a liquid metal, into a reservoir at the bottom of a glass tube. As the mercury got warmer, it expanded and rose higher in the tube. Thus, temperature was measured in relation to a fixed point. Some people used the local temperature for this fixed point—a hot summer day in London, or a cold cellar deep under a Paris observatory—or used the temperature of melting ice mixed with salt. One even used the blood of a dying ox. As a result, there were around thirty different scales to choose from.
Among the experimenters was Linnaeus’s friend and colleague Anders Celsius. A nephew of Linnaeus’s mentor in Uppsala, Olof Celsius, he was a physicist and the professor of astronomy in charge of Uppsala’s new observatory. Over two years, Celsius made remarkably precise measurements of water temperatures taking into account the influence of atmospheric pressure. He chose the points at which water boiled and started to freeze as the fixed points on his temperature scale. Unlike the hot London day and the cold Paris cellar, instrument makers in other parts of the world could replicate these two fixed points. However, Celsius’s thermometer was confusing visually. He put 0° (boiling) at the top and 100° (freezing) at the bottom, so it had increasing numbers for decreasing temperatures. That was awkward, a little like looking at the world while standing on your head.
Although it is not known what kind of thermometer Linnaeus used in Clifford’s hothouse, in 1743 (seven years later) he placed an order for a Celsius thermometer for the Uppsala garden, and asked Sweden’s top instrument maker, Daniel Ekström, for an easy modification—to flip the numbers. Now 100° was marked at the top, for water’s boiling point, and 0° at the bottom, for its freezing point—the way it is today. When the Uppsala greenhouse got hotter, the mercury rose and the number of degrees increased. When the greenhouse got colder, the mercury dropped into the danger zone heading toward 0°. This made it more intuitive and easier to understand. Linnaeus and Ekström weren’t the only ones making this simple change. Instrument makers in France and Switzerland also turned Celsius’s scale upside down.
The banana plant had been brought from somewhere in the Americas five years earlier. Since then it had “passed a miserable life,” said Linnaeus, “without any amorous incentive.”
A banana plant is monoecious, meaning it has both male flowers to produce pollen and female flowers to bear fruit on the same plant. So far, Clifford’s plant had produced neither flowers nor fruit. Did it lack something from its natural habitat? Maybe the soil, or the amount of water, wasn’t right. What would happen, Clifford asked his experts, if you could simulate the hot, humid conditions of the tropics, where bananas grow vigorously?
Linnaeus took up the suggestion. First, he and Nietzel needed to be able to measure temperature in the greenhouse. Back then, few people owned a thermometer. This meteorological instrument cost as much as a musket or a blacksmith’s wages for an entire month. Fortunately, cost was no problem for Mr. Clifford. So armed with the high-priced gauge, Linnaeus and Nietzel boosted the greenhouse’s temperature and humidity to mimic the tropics. Next, they repotted the plant in rich soil. They withheld water for a few weeks and then, to imitate a monsoonlike tropical downpour, they deluged the plant with water. They waited and watched.
About four months after their work began, on nearly the first day of the new year, the banana plant showed signs of change: From the center of its trunklike stem, a stalk called a peduncle pushed upward. At the tip, six whorls of maroon bud-shaped bracts appeared.
On January 24, the first bract opened. Like purple awnings over a window, the outer covering lifted and revealed a row of small, pale yellow flowers underneath.
Come early, Linnaeus urged in a letter scribbled hastily and delivered to his friend Burman. Come at dawn—no later than noon—to see our flower at its best. The next day, carriages began rolling up to Hartekamp with naturalists who wanted to see this extraordinary plant for themselves. Burman rushed out with friends—a lawyer, a merchant, and a professor from Amsterdam. Even the most important medical professor of the day, Dr. Herman Boerhaave—a man so famous that a letter from China reached him addressed only to “a Monsieur Boerhaave, Europa”—made the trip.
Over the next several days, the showy purple bracts opened one at a time outward from the peduncle, displaying many rows of small, pale flowers. “These flowers did not all grow fully on the same day,” Linnaeus wrote, “but succeeded one another step by step, day by day, with different qualities and differing natures.”
This illustration of Clifford’s banana plant from Linnaeus’s book Musa Cliffortiana, shows flowers emerging in groups, one row at a time.
Linnaeus made daily notes of progress. “What is the meaning of honeyed liquid in any flower?” he asked, looking for explanations and parallels. “What is analogous to this in animals? Why is it re-absorbed in flowers wherein more perfect fruit has appeared, and not in others?” Linnaeus dissected a leaf and, using a microscope, discovered many fine vessels, “like spiders’ webs, white, parallel and tenacious.”
On January 30, the sixth bract opened, unveiling the final flower cluster. To commemorate this dramatic event, Clifford commissioned an artist to create two pen-and-ink drawings. One shows the lofty plant with its eight enormous leaves, in a pot. The second shows the stalk with flowers rendered life-size and its parts neatly labeled.
Yet three weeks later, there was still no fruit.
Despite that inconvenient detail, Linneaus rushed a manuscript to the printer’s shop in Leiden, three hours away. The resulting forty-six-page book, Musa Cliffortiana (Clifford’s banana), was illustrated with two large fold-out copperplate engravings. Linnaeus divided the text into chapters on the species’ natural history, various names used across the world, physical characteristics, and natural habitat. He described human uses of the plant—its leaves for roofing material, clothing, umbrellas, and napkins; its fruit for making bread, drinks, medicines, and food. He even included rec
ipes from an Indian kitchen. The book’s focus on a single plant was an unusual format—a study of one species. Now this model is called a monograph and used routinely for papers on specialized topics.
In his chapter on natural history, Linnaeus described what he believed were the origins of this kind of plant in the warmest regions of Africa and Asia. He explained that it had later been transported to the Canary Islands, off the West African coast, and in 1516 to Santo Domingo in the Caribbean as a plantation crop. Today, however, scientists trace the origins of banana plants to Malaysia and to New Guinea in Oceania, where people cultivated it around 5000 BC.
In the chapter on names, Linnaeus explained that Musa, the scientific name then in use, was a Latinized adaptation of moaz, the vernacular Arabic name for the fruit. He believed that a scientific name should either honor a scientist or be taken from ancient Latin or Greek, and he worried that since the Muse was “a goddess of the ancients” some of his colleagues might take offense at a name that could be seen as honoring a pagan deity. He proposed that the name was instead a tribute to Antonius Musa, a physician of ancient Rome. But despite the convoluted reasoning, Linnaeus always enjoyed thinking of the plant as his great inspiration, his muse, and often played with the name’s double meaning in his writing.
In the book’s final chapter, he explained that some of his contemporaries believed the banana was the unnamed forbidden fruit in the biblical story of Paradise, while others were convinced the fruit came from an apple tree, a mandrake, a fig tree, or even a huge grapevine. Linnaeus declined to weigh in on the debate, on the grounds that it was not relevant to a scientific discussion. Nonetheless, over a decade later, in 1753, he finally chose a scientific name for the banana—Musa paradisiaca. The name, which means “the banana of Paradise,” suggested where he really stood on the issue.
