Hektoen International

A Journal of Medical Humanities

The Bancroft doctors: Edward, Daniel, and Nathaniel

Jonathan Davidson
Durham, North Carolina, United States

Quercitin is a flavonoid compound derived from quercitron, found in many plants and vegetables. It possesses anti-inflammatory, antioxidant, and other effects and has possible therapeutic value.1 Quercitin not only has medicinal properties, but for almost 100 years was the chief coloring agent used in the textile and printing industry. What is little known outside the dyeing industry is the somewhat unusual provenance of its name and discovery. Edward Bartholomew Bancroft (EBB), an American medical doctor who practiced initially in Surinam and subsequently in England, first reported on the presence of a yellow pigment under the outer bark of the black oak tree, which he called quercitron after the Latin words for oak (“quercus”) and lemon (“citrina”). Extracts of quercitron include quercitannic acid, once used in the tanning industry, and quercitin, used in dyeing; all three have properties as coloring substances. Although he was a medical doctor, Bancroft failed to investigate the medical applications of quercitron.2 Bancroft was a man of many talents and of some duplicity, too: besides his aptitude in medicine and biology, many years after his death it came to light that he was a double agent for the American and English sides during the time of the American Revolution, using London and Paris as his base.3 His life of espionage is well-chronicled by Schaeper and others. This report describes his medical and scientific contributions, and the involvement of two physician family members, a brother and son.

Edward Bartholomew Bancroft. Via Wikimedia.

Edward Bartholomew Bancroft (1744/5–1821)

Edward Bancroft was born in 1744/5 in Westfield, Massachusetts. His father died when Edward was a child. At one point in his education he was taught by Silas Deane, who later as diplomat became an associate of Bancroft in Paris. At the age of sixteen, Bancroft was apprenticed to Thomas Williams, a doctor in Connecticut. He also took an early interest in natural dyes and their extraction. In 1763, he left Dr. Williams and traveled to Surinam, where he was employed for three years as a plantation doctor. His time there was extraordinarily productive. In addition to medical practice, the young Bancroft studied the botany and zoology of the country, including poisons, vegetable dyes, and marine life. His studies led to the publications of An Essay on the Natural History of Guiana, in South America, written in epistolary form to his brother, Daniel, in 1766 and The History of Charles Wentworth, Esq, a largely autobiographical novel. He studied poisons, including the now well-known arrow poison used by the native inhabitants, which they called woorara and to which Bancroft gave the phonetically similar name “curare.”

During his time in Surinam, Bancroft experimented with electric eels and found they did not stun their prey through direct contact such as by slapping, as was the accepted theory at the time. In Bancroft’s experiments, subjects were tested without direct contact with the fish, and yet became electrocuted. Bancroft concluded that electrical impulses were transmitted through unidentified particles. His findings drew the interest of many prominent early pioneers in the field of electricity, such as Benjamin Franklin (1706–1790) and William Bryant (1730–1783), and ultimately led to the voltaic battery. Bancroft was a pioneer in the understanding of electricity and animal physiology.3,4 He also considered the possible therapeutic application of electricity, but without any positive findings.

Bancroft left Surinam for London in 1767, where he enrolled as a student at St. Bartholomew’s Hospital. In 1769, he returned for short trips to Surinam and Boston and then sailed back to England, which became his home. In 1774, at the age of thirty, he obtained an MD degree from Aberdeen University. One of his sponsors, Dr. George Fordyce, had been impressed by Bancroft’s work on dyes. The second sponsor, Dr. John Lettsom, was influential in other ways for co-founding the Medical Society in London, into which he recommended Bancroft for membership. Bancroft subsequently became secretary of that organization.

Medical contributions from his time in Surinam included descriptions of leprosy, yaws, gastroenteritis, infectious hepatitis, and venomous snake bites. On the recommendation of his friend Benjamin Franklin, Bancroft became a columnist in the London Monthly Review between 1774 and 1777, writing on revolutionary politics, science, and medicine. As far as the last of these was concerned, his writings were cautious and restrained.5 As Bancroft became drawn into the disputes between Crown and colonies, he devoted himself less to medicine, apart from some ministrations to his friends Franklin and Deane. He also collaborated with his son Nathaniel in editing and writing a forward for his book on yellow fever.

With regards to Bancroft’s oak bark interests, in 1775 he obtained an exclusive fourteen-year patent for importing oak bark into England, which was later extended out to 1799. In theory this should have brought a considerable income, given the demand for quercitron, but the combination of a trade embargo for American goods and subversion of Bancroft’s patent protection by the dyeing industry in Britain meant that Bancroft received only minimal income and did not cover his expenses. At one stage, his brother Daniel had arranged for shipment of raw material bark, but it never arrived in England, having been intercepted by British troops in America, who used it as firewood. Edward continued his studies into coloring and in 1794 and 1814 wrote and updated his widely read book Experimental Researches Concerning the Philosophy of Permanent Colors, which described thousands of his experiments. Mainly for his work with dyes, Bancroft had been elected to Fellowship of the Royal Society (FRS) in 1773, a distinction for one who was only twenty-eight years old.

In 1771, Bancroft married Penelope Fellows (1749–1784) and they had seven children, including Edward Nathaniel (ENB). Penelope died at the age of thirty-five, leaving the elder Edward to raise his young children. He never re-married.

In November 1804, Bancroft traveled to Surinam for several months to resume studies of the flora and fauna of that country and to gather more information on yellow fever to help his son’s work. In July 1805, Bancroft was back in London.

The last two decades of Bancroft’s life were years of decline, marred by bouts of illness and increasing poverty. The quercitron business had been of no significant financial benefit. In 1819, he wrote to his son in Jamaica, describing his health problems and saying, “If you do not soon relieve me, my struggles must end.”5 In the last years of his life, Bancroft lived with his daughter, Maria, in Margate, where he died on September 8, 1821.

Daniel Bancroft (1746–1796)

Daniel Bancroft was Edward’s younger brother. He was born in Westfield, Massachusetts on November 2, 1746. He received little formal education but must have found a benefactor, possibly his brother, who made it possible for Daniel to travel to Scotland to enroll as a medical student at the University of Edinburgh in 1769. He did not stay long enough to obtain a medical degree, and at the instigation of his brother in 1771, returned to America to pursue their black oak bark business and to practice medicine. Daniel was responsible for exporting cargoes of oak bark for Edward to extract and sell as an industrial dye. Daniel has been described as a mysterious figure,2 and proved to be a costly and unsatisfactory agent for Edward, eventually being replaced. Hansen2 noted that Daniel’s “mind was too much absorbed in scientific works to bend to business,” although no traces can be found of any scientific or medical accomplishments.

In 1775, as the revolution gained momentum, Daniel wrote to his brother explaining that his loyalty lay with the British Crown and that he intended to join the British army. From that point, there was no contact between the two brothers until November 1783, when Edward, on a visit to Philadelphia, contacted Daniel and persuaded him to return from New Brunswick, firstly via Philadelphia, then to Wilmington, Delaware, where he established his medical practice and made Wilmington into a major milling and distribution center for quercitron.3 pp. 64 & 232

Daniel married Mary Valleau on September 8, 1776 in Burlington, New Jersey. They moved to Philadelphia around 1776. While Philadelphia may have been a logical choice for the growth of that business, it presented serious problems for Daniel, as his Loyalist views set him at odds with the city’s revolutionary fervor. Suspected of being a spy, he was imprisoned by the royal authorities on December 22, 1776 and ultimately released after he took an oath of loyalty in April 1777. Following release, Bancroft was appointed ship’s surgeon on HMS Roebuck, the flagship of a British squadron blockading colonial ports.3 In 1780, he was serving as surgeon with the Second New Jersey Loyalist Volunteers in Savannah and Charleston. After the war ended, Bancroft moved to New Brunswick, where the British government awarded land grants to Loyalists. But after persuasion from his brother, he moved back to Delaware to practice medicine and resume their business partnership.

Edward Nathaniel Bancroft. From John Green’s Family Data. No known copyright restrictions.

Edward Nathaniel Bancroft (1772–1842)

Edward Nathaniel (ENB) was Edward Bartholomew’s (EBB’s) oldest child. He was educated privately at Dr. Burney’s School in London and matriculated at St. John’s College, Cambridge in 1779. He obtained MB and MD degrees in 1794 and 1804.6 In 1795, Bancroft took up an Army appointment and for the remainder of his career held full-time or part-time military positions. After initially serving in the Caribbean, Mediterranean, and Middle East, ENB returned to London in 1805, became Fellow of the Royal College of Physicians in 1806, Censor to the College in 1808, and a consultant at St. George’s Hospital in 1808. His highest achievement during this period was being invited to give the Goulstonian Lecture in 1806–7, for which he chose the topic of yellow fever. These lectures date back to 1639 and are given annually at the Royal College of Physicians, and to be invited represents high distinction.

Because of poor health, ENB had to quit his lucrative practice in London and move to a warmer climate. He settled in Jamaica, where he lived for the rest of his life, dying at age seventy in 1842. In Jamaica, his activities were varied and included work as a military doctor, deputy inspector of military hospitals, private medical practitioner, botanist, zoologist, and author.

Bancroft was well-regarded for his writings on yellow fever, in particular his 1811 book entitled Essay on the Disease Called Yellow Fever, with Observations Concerning Febrile Contagion, Typhus Fever, Dysentery and the Plague. According to Schaeper, 3 p. 260 one critic said of the book: “Never has any work effected a greater revolution in professional opinion in this country.” But despite its major impact, Bancroft’s views were flawed by his convictions that yellow fever was not contagious, and that yellow fever and malaria were identical. Bancroft also made observations on 99 cases of typhus, noting a latent period of 13 to 68 days in that disease.6

As a botanist, ENB discovered a type of hibiscus known today as Hibiscus Bancroftianus3; he also described a medicinal plant used as an emetic called cuichunchulli.6 As zoologist, in 1829 he reported on a form of manta (Manta americana Bancroft).7,8 Bancroft served as president of the Jamaican Society of Horticulture and Agriculture, and corresponding member of the London Horticultural Society and the Académie Royale de Médecine in France.


By any standard, EBB was a man driven by an inquiring mind, which led him to significant discoveries, particularly in the chemistry of plant-based colors, which found a ready uptake in the dyeing and tanning industries, lasting for almost a century. His scientific bent was accompanied by a commercial approach and strong entrepreneurial spirit, and he changed the face of the British calico printing industry. He was a risk-taker with an inclination to play the stock market, not always with success, and he ended up with financial difficulties. He was a well-respected physician in London who, at a young age, attained membership into some of England’s most privileged medical and scientific societies. His commercial inclinations drew him and his brother Daniel together in building the oak-bark business. Less is known about Daniel,9 but he did not appear to show the same scholarship as his brother and nephew. Like his brother, Daniel was caught in the crosshairs of revolution and had to pick sides. Nathaniel showed great interest in the natural world and in diseases, and achieved fame in scientific and medical circles. His views on yellow fever, which may have been seen as his major contribution at the time, were later discredited. One characteristic that all three Bancroft doctors had in common is that these talented men were thwarted in the full achievement of their ambitions by circumstance—the struggle for independence by the North American colonies in the case of EBB and Daniel, and by poor health in the case of ENB. Had conditions been more in their favor, one can wonder what their further contributions to science might have been.


  1. Yi H et al. “The therapeutic effects and mechanisms of quercitin on metabolic diseases: pharmacological data and clinical evidence.” Oxidative Medicine and Cellular Longevity 2021. https://doi.org/10.1155/2021/6678662.
  2. Hansen HN. “The quest for quercitron: Developing the story of a forgotten dye.” Dissertation, University of Delaware. Winter 2011.
  3. Schaeper TJ. Edward Bancroft. Scientist, Author, Spy. New Haven and London: Yale University Press, 2011.
  4. Finger S. “Edward Bancroft’s ‘torporific eels.’” Perspectives in Biology and Medicine 52, no. 1 (Winter 2009): 61-79.
  5. Anderson GT, Anderson DK. “Edward Bancroft, M.D., F.R.S. Aberrant ‘practitioner of physick.’” Medical History 17, no. 4 (Oct 1973): 356-67.
  6. MacNalty AS. “Edward Bancroft, MD., FRS., and the War of American Independence.” Proc Royal Society of Medicine 38, no. 1 (Nov 1944): 7-17.
  7. Bailly N. “Manta Bancroft, 1829.” WoRMS: World Register of Marine Species. https://www.marinespecies.org/aphia.php?p=taxdetails&id=105755&allchildren=1.
  8. Bancroft EN. “On the fish known in Jamaica as the Sea-Devil.” Zoological Journal 4, no. 16 (1829): 444-467.
  9. Rizzo D, McShulkis A. “The widow who saved a revolution.” Garden State Legacy. https://gardenstatelegacy.com/files/The_Widow_Who_Saved_a_Revolution_Rizzo_McShulkis_GSL18.pdf. Accessed Feb 20, 2024.

DR. JONATHAN DAVIDSON trained at University College Hospital, London, and practiced psychiatry at Duke University Medical Center. He has published extensively in the areas of post-traumatic stress, anxiety, depression, resilience, psychopharmacology, complementary and alternative medicine, and medical history and biography. 

One response

  1. WOW!! My first reaction is that they accomplished so much and lived relatively short lives, except for Daniel. Furthermore, it required much world travel which was not easy or quick at the time. I love EBB’s association with Benjamen Franklin, who I consider as the greatest American to ever live up to this point. He died at 83, was tall and a bit portly, but that wasn’t really a health concern for him.
    Then I think of you and your keen and productive research and medical history/biography, etc.
    Then I think of Martin Luther! Why? Because his movement some 500 years ago in Northern Germany allowed all sorts of new thinking/inquiry/research that did not need the blessing of the Catholic Church.
    When I was at Johns Hopkins, there was so much quality research going on. One was Solomon Snyder, second year resident when I was a first. He had already published 70 papers and had received the Lasker Award. Then, I had a running buddy in high school, Martin Robson. He went to JHH for his medical school training, became an internationally known plastic surgery having written over 500 papers on healing in those who had been severely burned. He died just last year at the age of 84. Thank you for sharing this and may you and Meg continue to thrive in peace and good health! – Chuck

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