Features appear in each issue of Pennsylvania Heritage showcasing a variety of subjects from various periods and geographic locations in Pennsylvania.

The life of naturalist Joseph Leidy (1823-1891) was one of quiet dedication, but revolutionary achievement. He preferred to allow his research, published findings, and academic distinction to speak for him. When the modest father of paleontology in North America died in Philadelphia on April 30, 1891, local institutions quickly paid tribute. The Academy of Natural Sciences immediately passed a resolution to express its sense of loss: “His charity, rectitude and humility endeared him to his associates, who loved the man while they admired the scholar.” The University of Pennsylvania announced it would drape the biology school building in black for thirty days as a sign of respect and for “our exalted appreciation of his genius and attainments.”

The Philadelphia Inquirer made plans to raise money for a statue of Leidy which still stands in front of the Academy of Natural Sciences, but it’s likely that most people who pass by know little, if anything, about the individual it memorializes. In his day, Leidy was one of the country’s leading scientists, engaging in pioneering work on everything from dinosaur fossils to microscopic parasites. “His encyclo­paedic knowledge, broad grasp of the whole field of natural history, precision and originality of observation in every field, present a combination of endowments which will never reappear in a single individual,” wrote Henry Fairfield Osborn (1857-1935), American paleontologist, geologist, and eugenicist. It’s little wonder that when Leon­ard Warren wrote the first published biography of Leidy, released by Yale University Press in 1998, he subtitled it The Last Man Who Knew Everything.

Joseph Leidy was born on September 9, 1823, in Philadelphia. His father, Philip (1791-1862), was a hatter of German descent who had married Cath­erine Mellick (1790-1825) in 1818. Joseph was their third child, but the first to survive infancy. Twenty months later Catherine died in childbirth with Joseph’s brother Thomas. Philip remarried in 1826 to Christiana Tatiana Mellick (1797-1881), his wife’s cousin. She was a loving stepmother to Joseph and his brother Thomas, and a good mother to the other six children she had with her husband. Leidy’s father was openly disdainful toward professional scientists and could not imagine earning a living in scientific observation.He thought young Joseph should learn a skilled trade in order to support a family. Although Joseph tolerated his father’s attitude, it was Christiana Leidy who shared her late cousin’s enlightened opinion of education. Joseph’s devotion to his stepmother was apparent in later life when he wrote, “She was the only mother I ever knew and to her I owe all that I am.”

Young Leidy quickly developed a love for the natural world around him. “I was what other boys would call a ‘queer boy,”‘ he recalled much later. “I never cared about joining in their sports. I was always anxious to see how plants and animals are made, as other boys were curious about the internal construction of their toys.” When other boys went outside for school recess, Leidy sat at his desk and sketched natural objects or landscapes. Such boys are obvious targets for bullies, so Leidy’s parents found a young African American, Cyrus Burris, to act as the youth’s companion and protector. Together, the boys, who became lifetime friends, roamed about Philadelphia examining the plants and animals they found. By the time he turned ten, Leidy had filled a notebook with drawings of shells. Leidy’s stepmother believed his artistic talent would make a good doctor, but his father wanted his son to apply that ability towards a practical end and suggested that Joseph become a sign painter. At the age of seventeen, in 1840, Leidy enrolled in the medical school of the University of Pennsylvania, an institution with which he would remain associated for nearly a half century, until his demise.

Leidy showed little affinity for medicine and practiced only two years. He preferred natural science and became an assistant to William E. Horner, University of Pennsylvania professor of anatomy. Horner took Leidy on a scientific tour of Europe in 1848 that improved his standing in academic circles. The non-confrontational Leidy claimed a professorship at the university only after engaging in a political battle against another candidate, an experience he vowed to never repeat. By 1853, Leidy would succeed Horner as professor of anatomy and would be regarded as a leading authority on parasitology.

The professorship was just one of Leidy’s rewards for unrelenting dedication to his work. In 1845, a paper he had written on mollusks at the age of twenty-two earned him election to the Boston Society of Natural History. That same year he was also invited to join Philadelphia’s equally prestigious Academy of Natural Sciences. Established in 1812 as a “meeting of gentlemen, friends of science and of rational disposure of leisure moments,” the academy had become one of the foremost scientific societies in the United States, with a library of 25,000 volumes, 245 members and 520 correspondents. Leidy became such an integral part of the institution during his forty-six years as a member that “to the community at large, the names of Leidy and the academy were inseparably associated.”

Leidy made occasional forays outside of the greater Delaware Val­ley, including trips to Europe and a brief expedition to the American West in 1872 to search for fossils in Wyoming’s Bridger Basin, but he did not have to travel far for his work. He found material for his observations wherever he happened to be. “On his daily walk from his home on Third Street to his work on Ninth, perhaps ten city blocks, Leidy, an urban naturalist, would find something of biological concern in a garden, on the street, or in the markets, where vendors were alerted to his interests,” wrote Warren, his biographer. He made one of his most important discoveries in 1846 at his own breakfast table, when he observed tiny white flecks in the pork he was eating. They were Trichina spiralis, the larvae of the worm that causes trichinosis. Leidy’s discovery helped pave the way to the discovery of the life cycle of this sometimes fatal parasite.

Leidy was aided in such discoveries by his pioneering use of the microscope, which he called his “first love.” The instrument had yet to be fully appreciated by scientists in the United States before the 1840s, but it was a natural fit for an observer such as Leidy. He used it to study the liver, insects, fossils, and blood – even using it in 1846 as a forensic tool when police asked him to examine bloodstains in a murder case. His publication in 1854 of A Flom and Fauna Within Living Animals opened ways to study the parasites that exist within other creatures.

Leidy also studied some of the largest creatures to Live on earth, identifying huge extinct mammals such as the titantothere, also known as the brontothere, a two-ton, eight-foot shoulder height, distant relative of the rhinoceros, from fossil bones that collectors sent him. He also recognized that horses had lived in North America long before the Spanish reintroduced them – a discovery that later helped support Charles Darwin’s theory of evolution.

When Leidy began studying the fossils of long-extinct animals, geology in the modern sense was still a new science, having been revolutionized by Great Britain’s Charles Lyell when he published his Principles of Geology in 1830. The study of dinosaurs had been moving forward steadily in Britain thanks to discoveries by Gideon Mantell, who identified and named Iguanodon in 1825, and later by Rich­ard Owen, who in 1841 coined the word dinosaur, derived from the Greek deinos, meaning monstrous, and sauros, meaning lizard. Until the mid-nineteenth century, no one had yet identified dinosaurs in North America.

The first dinosaur fossils Leidy identified were several teeth that had been recovered by Ferdinand Vandeveer Hayden (1829-1887). Like Leidy, Hayden had studied medicine, but longed to do something else. He found his calling as an explorer. In 1853, Hayden organized exploration of the Badlands in present­-day southwest South Dakota with funding from the state of New York. The Badlands contains the world’s richest deposits of fossils from the Oligocene epoch (thirty-four to twenty-three million years ago). When Hayden was preparing to head out again the following year for an expedi­tion to the land of the Upper Missouri, Leidy contacted him. “If I can be of any service to you, or can in any way promote your objects let me know it,” he wrote. “If you wish to make a sale of any of your specimens, for further explorations, l will see what may be done by subscription in our Academy.”

Hayden’s work was neither easy nor safe. Westward expansion by white explorers and pioneers had fomented hostile reaction by the Lakota (Sioux) natives. “Now Hayden’s fossil collecting ground became dangerous,” wrote Url Lanham in The Bone Hunters, “but legend has it that the Indians, who called him ‘the man who picks up stones while running,’ thought Hayden insane, and thus a holy man, a person not to be harmed.” Tn 1856-1857, Hayden explored the lands along the Judith River, in what is now Montana, where he collected fossil teeth, which he sent to Leidy. Leidy named the re­lated animals Trachodon (later renamed Anatotitan copei), Paleoscincus [costatus] (now identified as Edmontonia and Panoplosaurus), Troodon (not matched with the correct dinosaur until the 1980s), and Deinodon. They were the first fossils of dinosaurs identified in North America.

Not long after the Hayden’s discoveries, an exciting find was made closer to home. In 1858, a member of the Academy of Natural Sciences, William Parker Foulke, was vacationing in Haddonfield, New Jersey, when a farmer mentioned that large bones had been found twenty years earlier in the area. Foulke obtained permission to dig on the property and led a team that discovered sharks’ teeth, seashells, and other fossils. He alerted Leidy and, after further excavation, uncovered the fossil bones of a huge prehistoric reptile, which Leidy christened Hadrosaurus foulkii in recognition of Foulke’s find. Departing from the views of Richard Owen, Leidy decided that this beast had not crawled on its belly like a reptile, but stood on its hind legs like a kangaroo. Benjamin Waterhouse Hawkins, who had created life-size dinosaur models for London’s fabled Crystal Palace, beginning in 1852, volunteered to reconstruct the skeleton, using his imagination to fill in the missing material.

Leidy placed the reconstruction on display at the Academy of Natural Sciences, marking the first time a nearly complete dinosaur skeleton had been reassembled.

Joseph Leidy’s work in anatomy and the 1861 publication of his An Elementary Treatise on Human Anatomy established him as the leading authority on anatomy during the Civil War. His expertise proved valuable to the Union side during the war and in June 1862, he began serving as a pathologist for the Satter­lee Military Hospital in Philadelphia. By September, he had been appointed chief surgeon for Philadelphia and worked to help prevent gastrointestinal disorders among soldiers and determined the medical fitness of draftees. His service came with the sacrifice of his younger brother Asher Leidy being seriously wounded in the war and an interruption of his natural history research. He did find time, however, to present natural history lectures at the University of Pennsylvania which were open to the public and proved so popular that he continued giving them until 1867.

In 1865, after a hiatus of five years, Leidy published the fruit of his labors among the dinosaurs, Cretaceous Reptiles of the United States, a “dry, detailed account” that was, in the words of Leonard Warren, “free from speculation and generalization.” In Britain an anonymous critic – some believe it was Thomas Huxley, whose fierce defense of the theory of evolution earned him the nickname “Darwin’s Bulldog” – tore into the work. “Its best praise is that it contains no quackery; its worst condemnation is that it contains no science,” the critic harshly opined. This caustic response was an indication that Leidy’s style of purely observational work was becoming outmoded.

The paleontological landscape shifted dramatically when two new personalities appeared on the scene. Othniel Charles Marsh (1831-1899) was outwardly somewhat slow and cold – his nickname in college was “The Great Dismal Swamp” – but his cool exterior masked great ambi­tion. The ambition of the second personal­ity, Edward Drinker Cope (1840-1897), was more obvious (see “Edward Drinker Cope: Pennsylvania’s Greatest Naturalist,” by Spencer G. Lucas and Robert M. Sullivan, Fall 2005). Like Leidy, Cope was a Philadelphia native and by the age of eight he was describing specimens in the academy’s collections. Yet, Cope’s demeanor was completely different from Leidy’s. He was irascible and driven, the type of individual who embraced controversy with gusto. “Despite his greatness – in some measure, indeed, because of it – he had some unfortunate personal peculiarities, was pugnacious and quarrelsome and made many enemies,” remembered a fellow paleontologist. ironically, Cope was a Quaker, yet occasionally resorted to fistfights to settle scientific arguments. When Cope and Marsh both set their sights on the fossil discoveries being made in the American West, trouble was bound to follow.

In the 1870s, Cope and Marsh began waging what became known as the epic “bone wars,” bitter contests fueled by mutual animosity as each vied to identify the greatest number of new species. Although he was not responsible for the rivalry, Leidy did inadvertently help fan the flames. Cope, once Leidy’s student had assembled a fossil skeleton of an Elnsmosaurus, an aquatic reptile with a long head and neck, for display at the Academy of Natural Sciences. Cope showed the skeleton to Marsh who, to his great glee, noticed that his rival had placed the skull on the end of the tail, not on the neck. Leidy seconded Marsh’s opinion and even presented a correction at an academy meeting on March 81 1870. According to Marsh, Cope’s “wounded vanity received a shock from which it has never recovered, and he has since been my bitter enemy.”

Even in retreat Joseph Leidy could not rid himself of Edward Drinker Cope, who remained a “storm center” within the academy. Cope continually thrust himself into the forefront of struggles over the institution’s direction, and time and time again Leidy was reluctantly forced to take sides against him. Nonetheless, in his will Cope directed that his ashes be kept in the same place as Leidy’s remains.

As hostilities escalated, Leidy found himself relegated to the sidelines. Non-competitive by nature with a “morbid dislike of disagreement and contention,” Leidy preferred to remain outside the fray. “Formerly every fossil found in the States came to me, for nobody else cared to study such things,” he wrote to a colleague, “but now Professors Marsh and Cope, with long purses, offer money for what used to come to me for nothing, and in that respect I cannot compete with them. So now, as I get nothing, I have gone back to my microscope and my rhizopods and make myself busy and happy with them.”

Leidy remained an important facilitator of academic research and studies at the University of Pennsylvania and, as of 1871, in a concurrent professorship at Swarth­more College, a Quaker institution west of Philadelphia. At Swarthmore, Leidy lectured on natural history, mineralogy, and geology, established and curated a natural history museum, and oversaw the establishment of a library. He continued at Swarthmore until 1885 when he became director of the new biology department that he created at the University of Penn­sylvania. At the same time, he became lead curator and faculty president of Philadelphia’s Wagner Free Institute of Science, founded in 1855.

In 1859, Darwin published The Origin of Species and introduced his theory of evolution to the world. Leidy was delighted by the work. “I felt as though I had groped about in dark­ness, and that all of a sudden, a meteor flashed upon the skies,” he wrote to Darwin. In fact, Leidy had been think­ing along the same evolutionary lines. In the introduction to A Flora and Fauna within Living Animals, published six years earlier, Leidy had written, “The study of the earth’s crust teaches us very many species of plants and animals became extinct at successive periods, while other races originated to occupy their places. This probably was the result, in many cases, of a change in exterior conditions incompatible with the life of certain species and favorable to the primitive production of others .. .. There appears to be but trifling steps from the oscillating particle of inorganic matter to a bacterium … thence to a mouse, and so gradually up to the highest orders of life.” Leidy almost always avoided the temptation to stray from pure observation – as Henry Fairfield Osborn put it, he preferred the “plain, unvarnished statement of fact, unclouded by speculation” – and it was Darwin who ignited the debates that continue to this day.

Science was changing radically, but Joseph Leidy did not change with it. “The proliferation of its branches meant that individual scientists had to become more specialized,” wrote Robert V. Bruce in The Launching of Modern Ameri­can Science. “The growing complexity of science demanded formal scientific education and full-time professional work, not the casual, intermittent atten­tion of self-taught amateurs.” Theory and experimentation were replacing Leidy’s technique of neutral observation – just one reason for the decline of his reputation.

Despite his essential decency, his hard work, and bis remarkable breadth of knowledge, he was a modest and shy individual which did little to earn him a prominent niche in the annals of natural history. Married in August 1864 to Anna Harden, he enjoyed a happy and harmonious home life. People liked him – in some cases revered him – but outside his work he was placid, calm, seemingly colorless. “Leidy was a man of good cheer, striking good looks – one friend described him as ‘the Christ type’ – and a hankering for black bread, Swiss cheese, and lager beer,” wrote Mark Jaffe in The Gilded Dinosaur, his account of the Cope-Marsh feud. “He liked every­one, and everyone liked him.” A man of humble beginnings who strove to fit into the polite world of elite Victorian Philadelphia, Leidy hesitated to cause a stir. “He refused to theorize, to debate, and to defend – polite society might consider inordinate striving rather vul­gar and in poor taste,” opined Warren.

Joseph Leidy’s work brought professional recognition. In addition to be­ing one of the founders of the National Academy of Sciences in 1863, Leidy became director of the Philadelphia Zoological Society in 1876 and helped establish the Philadelphia Zoo. He received a number of coveted honors, among them the Boston Society of Natural History’s Walker Prize in 1880, the Lyell medal from the Geological Society of London in 1884, an honorary degree from Harvard University in 1886, and the Georges Cuvier Medal from the Academy of Sciences of Paris in 1888. He served as president of the American Association of Anatomists from 1888 to 1889.

Exhausted by overwork and suffering from arterial disease, Joseph Leidy died at the age of sixty-seven in 1891. His body was cremated, and the ashes – mingled with his wife’s after her death in 1913 – are now on display at Philadelphia’s Wistar Institute. Leidy donated his brain to the American Anthropometric Society for study and it is still in the organization’s collection. Even though he is largely forgotten, Joseph Leidy is a presence in his native Philadelphia, where a school, a street, and a college professorship bear his name. And then there’s the statue. that has stood, since 1930, in front of the academy to which Leidy devoted so much of bis time. The likeness of the great naturalist is uncanny: Leidy holds a fossil jaw bone under one arm and he peers ahead, his eyes wide open in permanent observation.


Travel Tips

Prehistoric history is continually being updated and museums around Pennsylvania offer visitors amazing journeys millions of years back in time (see “Destina­tion: The State Museum of Pennsylvania” on page 38 about the cast of a skull. of a newly named dinosaur displayed this summer in The State Museum’s Hall of Paleontology and Geology in Harrisburg.)

Since 1812, the Academy of Natural Sciences in Philadelphia has been world renowned, not only as a center of scientific research and study, but also for one of the finest collections of natural history and pa­leontology in the world. Ever since the first complete dinosaur skeleton in the United States was assembled and placed on display at the academy, the institution has continued to interpret, document, and educate the public about the natural world.

Through September 2006 , the academy is offering a series of programs that will fascinate visitors of all ages. “Bones: An Exhibit Inside You” explores bone biology, keeping bones healthy, and bones in world cultures, among other displays. Along with this and the permanent Dinosaur Hall exhibits, the academy is offering a series of special weekend programs. These include a vertebrate weekend where children will be delighted to touch actual bones and animal fur; a fossil weekend where fossil owners can have their specimen identified; and an exoskeleton weekend, an owl weekend, and programs where visitors can find out what anthropologists and forensic experts learn from bones.

Bone hunters can uncover more informatjon by writing: Academy of Natural Sciences, 1900 Ben Franklin Parkway, Philadelphia, PA 19103; by telephoning (215) 299-1000; or by visiting the Academy of Natural Sciences website.

In Lancaster, the North Museum of Natural History, southcentral Pennsylvania’s learning center to explore the natural world, displays curated collections and offers a Dinosaur Hall that includes a Tyranno­saurus rex waiting to greet visitors. With the third largest planetarium in Pennsylvania and hands-on programs in natural science designed to stimulate young minds, the museum offers both fun and educational experiences for the entire family. Programs are offered on everything from live snakes, turtles, and other animals, to field trips, lectures, exhibits, and other special events, inducting an “Insect Weekend” in July.

To plan a visit, write: North Museum of Natural History, 400 College Ave., Lancaster, PA 17603; telephone (717 ) 291-3941; or go on a virtual visit at the North Museum of Natural History website.

In western Pennsylvania, the Carnegie Museum of Natural History has one of the finest specimens of Tyrannosaurus rex skulls known to exist. Despite ongoing construction to enlarge Dinosaur Hall to three times its most recent size, visitors can still enjoy the Stegosaurus on display, and a mysterious new, but yet unnamed, species of oviraptorosaur. Construction of the new Dinosaur Hall is expected to be completed in late 2007 in time for the centennial of the first Dinosaur Hall, with the expansion providing a unique perspective. Visitors have a spectacular view into the Paleolab as scientists reconstruct the dinosaurs for exhibit, much of their work based on recent discoveries that have altered scientific thinking about bow dinosaurs actually looked. Construction progress and dinosaur work can also be witnessed through the museum’s online Webcams.

For more views of offerings, write: Carnegie Museum of Natural His­tory, 4400 Forbes Ave., Pittsburgh, PA 15213; telephone (412) 622-3131; or visit the Carnegie Museum of Natural His­tory website.


For Further Reading

Farlow, James O. and M.K. Brett-Surman, eds. The Complete Dinosaur. Indianapolis: Indiana University Press, 1997.

Garcia, Frank A. and Donald S. Miller. Discovering Fossils. Harrisburg: Stack­pole Books, 1998.

Leidy, Joseph. Researches in Helmin­thology and Parasitology. Washington, D.C.: Smithsonian Institution, 1904.

Sullivan, Robert M., Kesler A. Randall and Spencer G. Lucas. Natural History Notes of the State Museum of Pennsylvania. Harrisburg: Pennsylvania Historical and Museum Commission, 1996.

Warren, Leonard. Joseph Leidy: The Last Man Who Knew Everything. New Haven: Yale University, 1998.

Weishampel, David B. and Luther Young. Dinosaurs of the East Coast. Baltimore: The Johns Hopkins University Press, 1996.


The editor acknowledges the gracious assistance of Carolyn Belardo, communications manager of the Academy of Natural Sciences, for providing images to illustrate this article.


Tom Huntington is a freelance writer and former editor of Historic Traveler and American History magazines. His writ­ing has appeared in Smithsonian, Civil War Times, Air & Space, British Heri­tage, and Invention and Tedmology, among others. His Ben Franklin’s Phila­delphia: A Guide was recently published by Stackpole Books, Mechanicsburg.