- A dictionary of medical eponyms

Francis Xavier Dercum

Born  1856
Died  1931

Related eponyms

American neurologist, born August 10, 1856, Philadelphia; died April 24, 1931.

Biography of Francis Xavier Dercum

Francis Xavier Dercum, whose family originally came from England, was born in a period of intense political conflicts which culminated with the Civil War. His father, Ernest Dercum, was a successful bookseller and grain wholesaler, which made it possible to finance the son’s studies.

Francis Dercum graduated from Central High School and commenced his medical studies at the University of Pennsylvania, where he was conferred doctor of medicine in 1877. He soon embarked on a brilliant career. From 1878 to 1883 he was a demonstrator of histology and physiology at his alma mater under Joseph Gibbon Richardson (1836-1886) and worked with George Arthur Piersol (1856-1924), who later succeeded the great Joseph Leidy (1823-1891) as professor of anatomy at the University of Pennsylvania. Dercum later became associate professor of physiology with professor Harrison Allen (1841-1897). He lectured on practical biology and demonstrated various protozoa, alga and bacteria. In this way he obtained a solid foundation for what was later to be called bacteriology. He was very interested in natural history and early became a member of the Academy of National Sciences, where he was an active member and debater for many years. His particular medical interest was neuropathology, and early in his career he worked as a pathologist at the State Hospital for the Insane in Norristown, Montgomery County, Pennsylvania.

In 1884 Dercum succeeded Charles Karsner Mills (1845-1931) as head of the neurological clinic at the University of Pennsylvania. Already at this time he was fully active as a general practitioner and an accomplished diagnostician.

It was at this time the photographer and scientist Eadweard Muybridge (1830-1904) commenced his studies of the movements of horses. Movies had not yet been invented, and Muybridge took his pictures with an array of camera in which the shutters were released by electromagnets. The horses’ movements could then be studied by gluing the pictures to the inside of a cylinder which was then rotated. This laid the foundation for the coming movie industry, and his extensive studies and inventions were acknowledged by such pioneers of motion pictures as E. J. Marey, the Lumière brothers, and Thomas Edison.

Dercum had Muybridge photograph patients with a pathological gait pattern and patients with convulsions elicited through hypnosis. These pictures were the first to document neurological diseases.

Muybridge published an eleven volume work “Animal locomotion” with 100.00 photographs, in which volume 8 contained Dercum’s patients.

Dercum was one of the founders of the Philadelphia Neurological Society in 1884. He became a member of the American Neurological Society in 1885, president in 1886. In 1885 he also became a member of the College of Physicians of Philadelphia. In 1887 he received a post as neurologist at the Philadelphia Hospital, in which there was a surplus of neurological patients. Despite his private practice he continued in this voluntary service until 1911. In 1892 he married Elizabeth De Haven Comly who came from an old Philadelphia family.

In 1892 Dercum was appointed to the new chair of clinical neurology at the Jefferson Medical College in 1892 A separate clinic was established in 1900 and Dercum was then appointed professor of nervous end mental diseases. He headed this department until he was emerited in 1925.

Dercum’s colleague John Chalmers DaCosta portrays him in “The trials and triumphs of the surgeon and other literary gems”.

“He was particularly strong in teaching insanity and his demonstrations of these borderland cases which lie near but not in the dark continent of insanity were masterly. It was striking to hear him develop from a patient a story of an obsession of a morbid impulse, of a morbid act, of a delusion. In regard to that curious condition, hysteria, he actually convinced me that the condition is a reality and not clever acting. He would sum up a case like an able judge sums up from the bench. He was positive whenever it was possible to be positive, admitting doubts if doubts existed, and he always gave credit to others who deserved it. He showed that to the very basis of his nature he was a good doctor.”

Dr. Tom Bentley Throckmorton described Dercum's lectures:
“I shall never forget the first of Professor Dercum’s clinics that I attended. His ability to engage the attention of the students and then to hold it seemed almost uncanny. On this particular morning he demonstrated the difference between lesions involving the upper motor pathway and lesions involving the lower motor pathway. A patient who had suffered a cerebral haemorrhage, with the resultant hemiplegic state, was the first subject of discussion before the class. The spastic arm and leg, the scythelike swing of the palsied limb as the patient walked, the characteristic attitude of the affected arm, the weakness of the lower part of the face, the deviation of the tongue, the increased tendon reflexes, the patellar and ankle clonus and the extensor toe sign were all pointed out and then analysed with such clarity of thought and logical deductions as to hold the listeners spellbound.
In contrast, another patient was used as a demonstration of what lesions of the lower motor pathway produced. The patient was a child who had suffered from an attack of acute poliomyelitis which resulted in paralysis of both legs and one arm. Here, again, the professor pointed out the cardinal symptoms of a lower motor neuron involvement, such as lost tendon reflexes, flaccidity and atrophy of muscles with associated electrical reactions of degeneration, and an absence of pathologic toe signs.”

Together with William Osler (1849-1919), William Pepper (1843-1898) and others Dercum founded the Anthropological Society and agreed to leave their brains for study. His interest in philosophy also rendered him a doctor’s degree even in this topic. In 1927 he was elected president of the American Philosophical Society, where he had been a member for 35 years. He died on April 23, 1931, at a meeting of the APS, sitting in the famous “ladder library chair”, which hade been made by Benjamin Franklin, the founder of the American Philosophical Society. The newspaper Morning Ledger the following day wrote “Dr. Dercum dies as he presides over scientists”.

Dercum was publisher of the Textbook of nervous diseases by American authors, to which he himself contributed several chapters.

We thank Samuel W. M. Griffin for correcting an error. Francis and Elizabeth Dercum were his great-grandparents.


  • A clinical manual of mental diseases.
    Philadelphia and London, 1913; 2nd edition, 1917.
  • Hysteria and accident compensation. Philadelphia, 1916.
  • Rest, suggestion and other therapeutics measures in nervous and mental diseases. Philadelphia, 1917.
  • An essay on the physiology of mind.
    Philadelphia and London, 1922.
  • The biology of internal secretions. 1924.
  • The physiology of the mind. 1925. Obituary: Journal of the American Medical Association, Chicago, 1931, 96: 1639.
  • C. W. Burr:
    Memoir of Francis X Dercum.
    Transactions of the College of Physicians of Philadelphia, 1932, 54: 65-71.
  • Fischer:
    Dercum, Francis Xavier.
    In: Biographisches Lexicon der hervorragenden Ärzte. Berlin, Urban und Schwarzenberg, 1932: 309.
  • T. B. Throckmorton:
    Francis X Dercum: Physician, teacher and philosopher.
    Journal of Nervous and Mental Disease, Chicago, 1942, 96: 529-541.
  • J. C. DaCosta:
    Francis X Dercum.
    In F.E. Keller, editor: The trials and triumphs of the surgeon and other literary gems. Philadelphia: Dorrance & Company, 1944: 172-182.
  • P. Beighton, G. Beighton:
    Dercum, FX (1856-1931).
    In: The man and the syndrome. Berlin, Springer-Verlag, 1986: 208.
  • F. B. Wagner Jr:
    Francis X Dercum, MD, professor of nervous and mental diseases (1900-1925).
    In: Thomas Jefferson University. Tradition and Heritage. Philadelphia, Lea & Feibiger, 1989: 467-468.

What is an eponym?

An eponym is a word derived from the name of a person, whether real or fictional. A medical eponym is thus any word related to medicine, whose name is derived from a person.

What is Whonamedit?

Whonamedit.com is a biographical dictionary of medical eponyms. It is our ambition to present a complete survey of all medical phenomena named for a person, with a biography of that person.


Whonamedit? does not give medical advice.
This survey of medical eponyms and the persons behind them is meant as a general interest site only. No information found here must under any circumstances be used for medical purposes, diagnostically, therapeutically or otherwise. If you, or anybody close to you, is affected, or believe to be affected, by any condition mentioned here: see a doctor.