Bedside Observation: Sydenham's Method, His Diseases and His Legacy

Thomas Sydenham (1624–1689) is remembered less for any single cure than for a way of working. In a century when many learned physicians reasoned from ancient theories about the body’s humours, he argued that a doctor’s first job was to watch: to describe each illness so exactly, from its first sign to its last, that it could be recognised the next time it appeared, in the way a botanist recognises a particular plant. Historians have called him “the father of clinical observation” and “the reformer of clinical medicine”, and his portraits of fevers, gout and a childhood movement disorder are still quoted in medical journals more than three hundred years later.

This page follows that method and what came of it: the botanist’s model for sorting diseases, his preference for experience over hypothesis, the year-by-year record of London’s epidemics, scarlet fever told apart from measles, whooping cough, the “cooling” treatment of smallpox, hysteria and iron for the “green sickness”, gout described by a man who suffered it, and the 1686 account of Saint Vitus’s dance. It then turns to later research — the streptococcal and immune story behind Sydenham’s chorea, the urate crystals behind gout, the botanical model in later disease classification, and the Victorian society that bore his name. His treatments are reported as the history of his time, not as methods. His laudanum and his use of the Peruvian bark have their own pages in this wing.

Table of Contents

  1. Diseases as Species: The Botanist’s Method
  2. Experience Before Theory
  3. The Epidemic Constitutions of London
  4. Scarlet Fever, Measles and Whooping Cough
  5. Smallpox and the Cooling Regimen
  6. Hysteria and Iron for Chlorosis
  7. Gout Described from the Inside (1683)
  8. Saint Vitus’s Dance (1686)
  9. Sydenham’s Chorea Today: Streptococcus and the Brain
  10. Urate Crystals, Nosology and the Sydenham Society
  11. Key Research Papers
  12. Connections
  13. Featured Videos

1. Diseases as Species: The Botanist’s Method

Sydenham’s first book, Methodus curandi febres (“The Method of Curing Fevers”), appeared in 1666. Ten years later its third edition was enlarged and renamed Observationes medicae (“Medical Observations”, 1676), and it opened with a preface that set out his programme in a single comparison. In the 1848 English translation published by the Sydenham Society, he writes that “it is necessary that all diseases be reduced to definite and certain species, and that, with the same care which we see exhibited by botanists in their phytologies.”

A “phytology” was a plant book, and the point of the comparison was precision. Botanists of the seventeenth century were learning to separate one plant from its look-alikes by close description of leaf, flower and seed. Sydenham wanted diseases treated the same way, and he made the point with a homely image: “he would be a careless botanist, indeed, who contented himself with the general description of a thistle.” A doctor who spoke only of “a fever” was, in his view, that careless botanist; there were many fevers, and each had its own course, its own season and its own response to treatment.

Locke’s hand in the preface

The philosopher John Locke, who trained in medicine at Oxford, was Sydenham’s friend and sometimes went with him on visits to patients. Historians have long asked how far Locke helped shape Sydenham’s written work. The historian G. G. Meynell devoted a 2006 paper in Medical History specifically to Locke and the preface of the Observationes medicae, and Kenneth Dewhurst earlier published a smallpox treatise of Sydenham’s that carries a preface and a dedication written by Locke (see section 5). The partnership of the two men — a working physician and a philosopher of knowledge drawn from experience — is part of why the 1676 preface is read today as a document in the history of science as well as of medicine.

The idea of sorting diseases like plants outlived both men. Later physicians, above all the French botanist-physician François Boissier de Sauvages and the Swedish naturalist Carl Linnaeus, built whole classifications of disease on it in the eighteenth century — a line of descent traced in section 10.

Back to Table of Contents

2. Experience Before Theory

Sydenham did not reject learning, but he distrusted systems of medicine built from reasoning about hidden causes. In his 1680 letter to the physician Robert Brady he describes the physician’s proper task as the “industrious investigation of the history of diseases and of the effect of remedies, as shown by the only true teacher — experience.” The word “history” here meant a careful natural history: what the illness looked like, in what order its signs appeared, how long it lasted and how it ended.

The medical historian A. W. Sloan summed up this side of him in 1987: Sydenham believed medicine was best learned by observing patients rather than by reading books, he kept meticulous records, and those records helped pave the way for the clinical approach of later centuries. Sloan also notes the other side — that his actual treatments were largely traditional. Sydenham bled, purged and prescribed much as his colleagues did; what set him apart was the attention he paid to the patient in front of him and the honesty with which he wrote down what happened.

The tension between his empiricism and the rationalist medical theories of his day is the subject of a 1970 study by Lester S. King in the Bulletin of the History of Medicine. His insistence on experience shows clearly in his writing on the Peruvian bark: when other physicians explained the bark’s effect on agues as mere astringency, Sydenham answered that those who thought so might try other astringents — “I know none that take effect.” Observation, not a plausible theory, settled the question for him.

Back to Table of Contents

3. The Epidemic Constitutions of London

By the early 1660s Sydenham practised in Westminster, and he used his London practice as a kind of observatory. Year after year he recorded which fevers and epidemic illnesses were prevalent, how they behaved, and how they changed from one season to the next. The Observationes medicae is organised around these records, with chapters on the “epidemic constitutions” of 1661 to 1664 and of the years that followed.

An “epidemic constitution” was Sydenham’s name for the prevailing character of a particular stretch of years: a period in which certain fevers dominated and other diseases took on a matching colour, before the pattern shifted and a new constitution took over. He did not know about bacteria or viruses — microbes would not be linked to disease for another two centuries — and he looked for the cause in some unknown change in the air. But the habit of recording which illnesses were present, when, and in what form, is recognisably the habit of the later epidemiologist.

His notes covered the years of the Great Plague of 1665. The second edition of the Methodus (1668) added a chapter on plague, and his 1680 letters continued the discussion of London’s epidemics. It was within this year-by-year record that his descriptions of individual diseases — the dysentery for which he prepared his laudanum, the agues he later treated with bark, scarlet fever and measles — first appeared.

Back to Table of Contents

4. Scarlet Fever, Measles and Whooping Cough

Rashes were a particular puzzle for seventeenth-century doctors, because many fevers produced them and they were easily lumped together. Sydenham is credited with describing scarlet fever (scarlatina) as a disease distinct from measles. In the Latham translation he describes its rash as “small red maculae, thicker than those of measles, as well as broader, redder, and less uniform,” and adds that afterwards “the cuticle peels off” — the peeling of the outer skin that is still recognised as a feature of the illness during recovery.

He also wrote at length about measles itself, separating its sequence of signs from those of smallpox and scarlet fever. Being able to tell these apart at the bedside mattered: the three had very different outlooks, and a doctor who confused them could not judge how worried a family ought to be.

Today scarlet fever is known to be caused by group A Streptococcus bacteria, usually following a sore throat, while measles is caused by a virus — a distinction Sydenham could not have made, but which matches the separation he drew from the look and course of the illnesses alone.

Whooping cough

Sydenham also described whooping cough, and the index of the Sydenham Society translation lists it under both “Pertussis” and “Hooping-cough” in the epidemic chapters of the Observationes medicae. Some modern summaries credit him with giving the illness the Latin name pertussis in a particular year; that date could not be confirmed in his collected works, so this page records only that he described the disease under that name. The bacterium responsible, Bordetella pertussis, was identified in the twentieth century.

Back to Table of Contents

5. Smallpox and the Cooling Regimen

Smallpox was one of the great killers of Sydenham’s London, and the common treatment of the time was to keep the patient hot — heaped with bedclothes in a closed, warm room, and given heating cordials — on the theory that the disease had to be driven out through the skin. Sydenham broke with this. As Latham’s life of Sydenham records, the short biographies of his day remembered him above all for three things: his laudanum, his administration of the Peruvian bark in agues, and “his cooling treatment of the smallpox.”

Under his regimen the patient was not kept smothered in bed all day; for part of the day the patient was kept out of bed, and the sickroom was not overheated, against the heating practice of the time. Sydenham defended this from what he had seen of how patients fared, not from a theory, and it was one of the things that brought him both admirers and fierce critics among his colleagues.

His writing on smallpox continued in the Dissertatio epistolaris of 1682, a long letter to the physician William Cole on smallpox and hysteria. In 1959 the historian Kenneth Dewhurst published an earlier, original treatise on smallpox by Sydenham, accompanied by a preface and a dedication to the Earl of Shaftesbury written by John Locke — further evidence of how closely the two men worked.

Smallpox itself was declared eradicated worldwide in 1980, after a global vaccination campaign that grew out of Edward Jenner’s work with cowpox more than a century after Sydenham’s death.

Back to Table of Contents

6. Hysteria and Iron for Chlorosis

Hysteria

The 1682 letter to Cole also contains one of the most detailed early accounts of what physicians then called hysteria in women and hypochondriasis in men. The older idea, going back to ancient Greek medicine, tied hysteria to the womb. Sydenham described it instead as a disorder that could imitate almost any other disease — producing pains, convulsions, breathlessness and many other symptoms with no matching physical damage — and he noted that it was among the commonest of all chronic complaints and that men suffered its counterpart too.

The neurologist J. M. S. Pearce reproduced Sydenham’s text on hysteria in 2016 and compared it with modern concepts, and the historian J. M. Boss examined in 1979 how the “hysteric affection” was transformed in the seventeenth century under Sydenham’s observational, Baconian style of medicine. “Hysteria” is a historical term that medicine has since abandoned; many of the presentations Sydenham described would today be discussed under the heading of functional neurological symptom disorder, also called conversion disorder. It is presented here as the history of a medical idea.

Iron for the “green sickness”

Chlorosis, the “green sickness”, was a condition of pale, tired, often breathless young women that physicians described for centuries; much of what was called chlorosis is now thought to have been iron-deficiency anaemia. Among the remedies Sydenham used was “steel” — iron filings or iron-rich chalybeate preparations — and he wrote of “the effects of steel upon chlorosis,” observing that “the pulse gains strength” as the patient improved. Iron was a mineral remedy long before anyone knew that it was a building block of haemoglobin, the protein that carries oxygen in red blood cells; Sydenham’s report is an early clinical record of what that mineral could do.

Back to Table of Contents

7. Gout Described from the Inside (1683)

Sydenham had gout for most of his adult life, from about 1649, and kidney stone as well. When he published his Tractatus de podagra et hydrope (“Treatise on Gout and Dropsy”) in 1683, he wrote as both doctor and patient, describing himself as “a man like myself, who has suffered from it thirty-four years.” In the dedication he says his “hand trembles too much to hold the pen” and thanks John Drake, a Bachelor of Medicine of Christ’s College, Cambridge, for his help.

His description of an attack is still quoted in the medical literature; a 2004 historical note in the Journal of Clinical Rheumatology returned to it. In the Latham translation:

“About two o’clock in the morning he is awakened by a severe pain in the great toe; more rarely in the heel, ankle, or instep. This pain is like that of a dislocation… it cannot bear the weight of the bedclothes nor the jar of a person walking in the room.”

Modern rheumatologists still recognise this picture: a sudden night-time attack, very often in the joint at the base of the big toe, so tender that even a bedsheet is unbearable. Gout had been known since ancient Egypt and Hippocrates, and was long called the “disease of kings”, but few earlier writers had set down its experience so vividly.

“Died of the medicine rather than the disease”

The treatise is also notable for its scepticism about the harsh treatments of the day. Sydenham wrote: “I confidently affirm that the greater part of those who are supposed to have died of gout, have died of the medicine rather than the disease — a statement in which I am supported by observation.” Coming from a physician who himself used bleeding and purging in other illnesses, it is a striking statement of the limits he saw in the medicine of his era, and it rests — as he says — on observation.

Gout and stone stayed with him to the end. He died at his house in Pall Mall on 29 December 1689; his Victorian biographer R. G. Latham records long gout and a kidney stone that caused copious bleeding into the urine. The full story of his life is told on the Life and Times page.

Back to Table of Contents

8. Saint Vitus’s Dance (1686)

For centuries “Saint Vitus’s dance” had been a loose name for outbreaks of uncontrolled movement. In his short Schedula monitoria of 1686, Sydenham described a specific childhood disorder under that name so clearly that it has carried his own name ever since: Sydenham’s chorea. In the Latham translation:

“a sort of convulsion which attacks boys and girls from the tenth year until they have done growing. At first it shows itself by a halting, or rather an unsteady movement of one of the legs, which the patient drags. Then it is seen in the hand of the same side… If any vessel filled with drink be put into his hand, before it reaches his mouth he will exhibit a thousand gesticulations like a mountebank.”

The passage captures the essentials that neurologists still describe: onset in later childhood, irregular, jerky movements that often begin on one side, and clumsiness that makes simple tasks such as drinking from a cup almost impossible. Sydenham’s own treatment for it was bleeding and purging, the standard measures of his time; they are recorded here only as history.

What Sydenham could not see was the connection between this chorea and an earlier infection. In the nineteenth century physicians, among them Richard Bright, linked chorea with rheumatism and heart disease, and J. M. S. Pearce’s 1995 note in the Journal of Neurology, Neurosurgery and Psychiatry discusses Sydenham’s and Bright’s accounts side by side.

Back to Table of Contents

9. Sydenham’s Chorea Today: Streptococcus and the Brain

Three centuries after Sydenham’s description, his chorea is understood as the neurological expression of acute rheumatic fever — an illness that can follow a throat infection with group A Streptococcus, the same bacterium that causes strep throat and scarlet fever. In a 2011 review in the Handbook of Clinical Neurology, the neurologist Francisco Cardoso describes it as the most common cause of acute chorea in children, with both movement (motor) and non-motor features. Chorea is one of the major diagnostic criteria for acute rheumatic fever. Most cases remit, but Cardoso reports that a significant proportion persist.

Antibodies that mistake the brain for the bacterium

The leading explanation is a case of mistaken identity in the immune system. Antibodies made against the streptococcus cross-react with nerve cells in the basal ganglia, a cluster of deep brain structures that help control movement. Cardoso’s review summarises this cross-reaction; a 2016 review by M. W. Cunningham and C. J. Cox in Acta Physiologica reports that human monoclonal antibodies derived from people with Sydenham’s chorea target the dopamine D2 receptor, one of the brain’s main receivers for the chemical messenger dopamine, and that anti-D2 receptor antibodies are raised in Sydenham’s chorea and in acute PANDAS (paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections). The authors disclose a financial interest in a diagnostic laboratory.

More than movement

The illness Sydenham described as a disorder of movement turns out to affect behaviour and mood as well. A 2016 systematic review of 49 papers by Punukollu and colleagues in Developmental Medicine & Child Neurology found obsessive-compulsive symptoms to be the most studied neuropsychiatric feature, with attention-deficit hyperactivity, mood disturbance, tics, problems with executive function and psychotic features also reported. A 2003 review by Bonthius and Karacay was titled simply “Sydenham’s chorea: not gone and not forgotten” — a reminder that, although rheumatic fever has become uncommon in many wealthy countries, it has not disappeared.

Back to Table of Contents

10. Urate Crystals, Nosology and the Sydenham Society

What causes the attack he described

Sydenham could describe a gout attack in exact detail but could only guess at its cause. The answer came in 1961, when Daniel McCarty and Joseph Hollander reported in the Annals of Internal Medicine the identification of urate crystals in the joint fluid of people with gout. The painful attack is now understood as the body’s inflammatory reaction to needle-shaped crystals of monosodium urate, which form when uric acid in the blood rises high enough to come out of solution. Gout can be confirmed by finding those crystals in fluid drawn from the joint, and blood uric acid is measured in the uric acid test.

The medicines followed a long path that began, like so many in this section of the site, with a plant. In their concise history of gout, George Nuki and Peter Simkin trace colchicine back to the autumn crocus, used for joint pain in late antiquity by Alexander of Tralles, and describe the later arrival of the uricosuric drugs (which help the kidneys clear uric acid) in the late nineteenth century and of the xanthine oxidase inhibitors (which reduce how much uric acid the body makes) in the twentieth.

The botanist’s model in later nosology

Nosology is the classification of diseases. Sydenham’s 1676 call to sort diseases into species “as botanists” sort plants became a working programme in the eighteenth century, when Sauvages and Linnaeus produced whole classifications of disease laid out like plant catalogues. In a 2018 paper in History of Psychiatry, Daniel Mason and Honor Hsin trace this botanical model of disease classification from the nosologies of Sydenham, Sauvages and Linnaeus to the psychiatrists Emil Kraepelin and Karl Jaspers, and into the present day — a line that runs, in a sense, to every modern manual that sorts illnesses into named categories with defined features.

The Sydenham Society and his reputation

In 1843 a group of physicians founded the Sydenham Society in London to publish English translations of classic medical texts; its two-volume Works of Thomas Sydenham, translated by R. G. Latham from Greenhill’s Latin edition (1848–1850), is the source of the quotations on this page. A New Sydenham Society carried the work on later in the nineteenth century. A statue of Sydenham stands in the Oxford University Museum of Natural History.

His reputation as the physician who put the bedside first has only grown. Short biographies in modern journals carry titles such as “the father of clinical observation” and “reformer of clinical medicine”, and his name lives on in the chorea he described and in the habit — now so ordinary that it is easy to forget it had to be argued for — of learning disease from the patient rather than from the book.

Back to Table of Contents

Key Research Papers

  1. Bloch H. Thomas Sydenham, MD (1624-1689): the father of clinical observation. J Fam Pract. 1994;38(1):80-1. PubMed PMID: 8289057
  2. Dewhurst K. Thomas Sydenham (1624-1689) reformer of clinical medicine. Med Hist. 1962;6(2):101-18. PubMed PMID: 16562238
  3. Sloan AW. Thomas Sydenham, 1624-1689. S Afr Med J. 1987;72(4):275-8. PubMed PMID: 3303370
  4. King LS. Empiricism and rationalism in the works of Thomas Sydenham. Bull Hist Med. 1970;44(1):1-11. PubMed PMID: 4909172
  5. Meynell GG. John Locke and the preface to Thomas Sydenham's Observationes medicae. Med Hist. 2006;50(1):93-110. PubMed PMID: 16502873
  6. Dewhurst K. Sydenham's original treatise on smallpox with a preface, and dedication to the Earl of Shaftesbury, by John Locke. Med Hist. 1959;3(4):278-302. PubMed PMID: 13816328
  7. Pearce JM. Sydenham on Hysteria. Eur Neurol. 2016;76(3-4):175-181. PubMed PMID: 27658273
  8. Boss JM. The seventeenth-century transformation of the hysteric affection, and Sydenham's Baconian medicine. Psychol Med. 1979;9(2):221-34. PubMed PMID: 382219
  9. Dorwart BB. Thomas sydenham (1624-1689), on gout: 1717. J Clin Rheumatol. 2004;10(4):227. PubMed PMID: 17043515
  10. Pearce JM. Thomas Sydenham and Richard Bright on chorea. J Neurol Neurosurg Psychiatry. 1995;58(3):319. PubMed PMID: 7897413
  11. Cardoso F. Sydenham's chorea. Handb Clin Neurol. 2011;100:221-9. PubMed PMID: 21496581
  12. Cunningham MW, Cox CJ. Autoimmunity against dopamine receptors in neuropsychiatric and movement disorders: a review of Sydenham chorea and beyond. Acta Physiol (Oxf). 2016;216(1):90-100. PubMed PMID: 26454143
  13. Punukollu M, Mushet N, Linney M, Hennessy C, Morton M. Neuropsychiatric manifestations of Sydenham's chorea: a systematic review. Dev Med Child Neurol. 2016;58(1):16-28. PubMed PMID: 25926089
  14. Bonthius DJ, Karacay B. Sydenham's chorea: not gone and not forgotten. Semin Pediatr Neurol. 2003;10(1):11-9. PubMed PMID: 12785743
  15. McCarty DJ, Hollander JL. Identification of urate crystals in gouty synovial fluid. Ann Intern Med. 1961;54:452-60. PubMed PMID: 13773775
  16. Nuki G, Simkin PA. A concise history of gout and hyperuricemia and their treatment. Arthritis Res Ther. 2006;8 Suppl 1(Suppl 1):S1. PubMed PMID: 16820040
  17. Mason D, Hsin H. 'A more perfect arrangement of plants': the botanical model in psychiatric nosology, 1676 to the present day. Hist Psychiatry. 2018;29(2):131-146. PubMed PMID: 29480060

PubMed Topic Searches

  1. Thomas Sydenham history
  2. Sydenham chorea and rheumatic fever
  3. Gout history and urate
  4. History of disease classification (nosology)

Further Reading

Back to Table of Contents

Connections