Magendie's Legacy: Claude Bernard, the Bell–Magendie Law and Experimental Medicine

François Magendie (1783–1855) is remembered in pharmacology for the poison experiments of 1809 and the Formulaire of 1821, which carried the newly purified plant alkaloids into medical practice. But the habit of mind behind those books — test every claim on a living animal, trust the experiment before the theory — spilled into almost every corner of physiology he touched. Spinal nerves, the cerebellum, the fluid that bathes the brain, the value of food, and the strange sudden deaths that followed a repeated injection all passed through his laboratory.

His most lasting legacy, though, may be a person. Claude Bernard, who became the most famous physiologist of nineteenth-century France, learned his craft at Magendie’s bench at the Collège de France and inherited his chair. This page follows what came after Magendie: the pupil, the discoveries that still carry his name, the priority quarrel with a Scottish anatomist, his early experiments on diet, the controversy his animal demonstrations caused, and how historians now judge the man and his method.

Table of Contents

  1. 1. Teacher of Claude Bernard
  2. 2. Bernard and the Arrow Poisons
  3. 3. Motor and Sensory Roots: The Bell–Magendie Law
  4. 4. A Priority Dispute Across the Channel
  5. 5. Cerebrospinal Fluid and the Foramen of Magendie
  6. 6. Dogs on Sugar and Water: Nitrogen and an Early Glimpse of Vitamins
  7. 7. The Gelatin Question
  8. 8. An Early Description of Anaphylaxis, 1839
  9. 9. The Vivisection Controversy
  10. 10. A Founder of Experimental Pharmacology
  11. Key Research Papers
  12. Connections
  13. Featured Videos

1. Teacher of Claude Bernard

Magendie took the chair of medicine at the Collège de France on 4 April 1831, succeeding J. C. A. Récamier. The Collège was not a medical school in the ordinary sense: it awarded no degrees, and its professors lectured on whatever they were researching. For Magendie that meant physiology demonstrated on living animals, in front of an audience.

The Collège de France’s own biography of Claude Bernard (1813–1878) sets out the stages of the relationship:

The two men worked side by side on at least one notable problem. In 1846 Magendie showed that sugar in the blood is not necessarily a sign of disease; the neurologist and historian J. M. S. Pearce notes that Bernard assisted. Blood sugar, the liver’s production of glucose and the idea of a stable internal environment later became the core of Bernard’s own reputation.

Bernard also left the best-known portrait of his teacher’s temperament. According to the Dictionary of Scientific Biography, Bernard recalled that Magendie compared himself to a ragpicker (chiffonnier) walking the field of science with a spiked stick and a basket, picking up whatever he came across. The image captures what admirers and critics both noticed: a restless collector of facts, more interested in what an experiment showed than in building a grand system. Historians have since examined the relationship between the two men and their different philosophies of science in some detail (Bloch 1989; Mazliak 2013).

Back to Table of Contents

2. Bernard and the Arrow Poisons

Magendie’s first great experiments, read to the Institut de France in April 1809 with the botanist-physician Alire Raffeneau-Delile, concerned a Javanese arrow poison called upas and the bitter Strychnos seeds, nux vomica and Saint-Ignatius bean. They showed that this whole family of plants acts powerfully on the spinal cord. That work is told on the companion page on the Formulaire and the first pure medicines.

Arrow poisons became a thread running from teacher to pupil. Claude Bernard took up the same family of problems and pushed them further, most famously with curare, the South American arrow poison he showed to act at the junction between nerve and muscle rather than on the nerve or the muscle itself. His unpublished laboratory notes on the physiological properties of arrow poisons — curare, upas, strychnine and others — survived, and were edited and published in 1966 by the historian of medicine Mirko Grmek, the same scholar who later wrote the Dictionary of Scientific Biography’s article on Magendie.

The continuity matters for the history of pharmacology. Magendie had established that a poison’s effect can be traced to a particular organ by careful experiment; Bernard used the same method to locate a drug’s action at a much finer level, at a single anatomical junction. Bernard’s curare experiments are described in detail on the Claude Bernard curare and carbon monoxide page.

Back to Table of Contents

3. Motor and Sensory Roots: The Bell–Magendie Law

Each spinal nerve joins the spinal cord by two roots: one leaving the front (anterior, or ventral) side of the cord and one leaving the back (posterior, or dorsal) side. In 1822 Magendie set out to learn what each root does.

The 1822 experiments

According to the historian Paul Mazliak’s commentary on the original papers (BibNum, 2023), Magendie worked on six-week-old puppies and cut either the anterior or the posterior roots. He published the results in his own Journal de physiologie expérimentale in August 1822, and a follow-up in October of the same year. His conclusion, in his own words, was that “les antérieures sont destinées au mouvement, tandis que les postérieures appartiennent plus particulièrement au sentiment” — the anterior roots serve movement, while the posterior roots belong more particularly to sensation.

Why it mattered

The finding is now taught as the Bell–Magendie law: motor fibres leave the spinal cord through the ventral roots, and sensory fibres enter through the dorsal roots. It is the anatomical basis of the reflex arc, in which a sensory signal enters the cord by one path and a motor command leaves it by another. It is also why a neurologist can often place a spinal injury precisely by testing which movements and which areas of skin have been affected. Tubbs and colleagues (2008) list the work on the dorsal and ventral roots among Magendie’s foundational contributions to neuroscience and neurosurgery. The animated reflex arc on this site shows the two paths.

Other work on the nervous system

The Dictionary of Scientific Biography records a run of further nervous-system experiments in 1823–1824: rigidity after the brain was separated from the lower nervous system (what is now called decerebrate rigidity), the role of the cerebellum in balance, the fifth cranial nerve as the nerve of facial sensation, and the circling “mouvement de manège” that followed a cut through a cerebellar peduncle (1824). Tubbs and colleagues add his use of galvanic current for neuralgias and his observations on pain arising from the meninges.

Back to Table of Contents

4. A Priority Dispute Across the Channel

The law bears two names because two men claimed it. The Scottish anatomist and surgeon Charles Bell (1774–1842) had in 1811 written a short pamphlet, Idea of a New Anatomy of the Brain, which he circulated privately among friends rather than publishing. In it, Mazliak notes, Bell gave the anterior roots a role in movement — but he connected the posterior roots with the cerebellum, not with sensation.

The two sides

What historians have made of it

The quarrel has become a classic case study in scientific priority. Rice (1987) examined it as a three-sided “Bell–Magendie–Walker controversy”, bringing in Alexander Walker as a third claimant. Jørgensen (2003) traced Bell’s theory, the law and the controversy alongside two forgotten Danish works on the same question by P. W. Lund and D. F. Eschricht. Drouin, Kwiatkowski and Hautecoeur revisited “the Bell–Magendie debate” in The Lancet Neurology in 2022. The common modern compromise is preserved in the name itself: Bell for an early anatomical idea, Magendie for the decisive experiment.

Back to Table of Contents

5. Cerebrospinal Fluid and the Foramen of Magendie

Between about 1824 and 1828, according to the Dictionary of Scientific Biography, Magendie studied the clear fluid that surrounds the brain and spinal cord: where it comes from, what it contains and how it moves. He described the opening in the roof of the fourth ventricle through which fluid passes from the ventricles of the brain into the space around it. Anatomy textbooks still call it the foramen of Magendie (the median aperture), and Tubbs and colleagues credit him with early work on extracting and analysing the fluid.

Magendie wanted to know whether the fluid was a secretion of the nervous system or simply filtered from the blood. As the historian of neurochemistry Theodore Sourkes (2002) describes, he asked chemists in Paris, among them Jean-Louis Lassaigne, to analyse samples — producing the earliest chemical analyses of cerebrospinal fluid. The question of how the fluid is made and drained is still studied; when its flow is blocked, fluid builds up inside the skull, the condition called hydrocephalus. The animated page on cerebrospinal fluid on this site shows its circulation.

Back to Table of Contents

6. Dogs on Sugar and Water: Nitrogen and an Early Glimpse of Vitamins

In 1816 Magendie published a memoir on the nutritive properties of substances that contain no nitrogen. Dogs fed only sugar (or other nitrogen-free foods) and water lost condition and died. The Dictionary of Scientific Biography reads this as an experimental demonstration that the diet must supply nitrogen — in modern terms, protein.

The eye lesions of 1817

One detail of these experiments has attracted later historians. The neurologist and historian Douglas Lanska (2010) notes that in 1817 Magendie reported ulceration of the cornea in dogs kept on sugar and water for weeks. Magendie attributed it to the lack of nitrogen. It is now recognised as a sign of vitamin A deficiency, the same process that damages the eye in children whose diet lacks the vitamin. Nobody in 1817 knew vitamins existed; the word itself was not coined for almost a century.

The nutrition scientist Clive McCay asked the question directly in the journal Science in 1930: “Was Magendie the first student of vitamins?” Grmek’s Dictionary article goes further, calling the experiment “the first experimental avitaminosis.” In 1951 the Journal of Nutrition published Fenton’s biographical memoir of Magendie. The site’s vitamin A deficiency page describes the eye changes in people.

Back to Table of Contents

7. The Gelatin Question

In the early nineteenth century gelatin, boiled out of bones, was widely seen as a cheap source of nourishment for hospitals and for the poor. Magendie’s experiments showed that gelatin alone had poor nutritive value, a finding that ran against hospital practice of the day.

The historian Frank Stahnisch (2004) studied Magendie’s feeding experiments on a gelatin diet between 1831 and 1841 under the title “Standardising hunger”. The question was a practical and political one: could gelatin feed the poor of Paris? Stahnisch shows how the experiments connected the Académie des sciences, food manufacturers and city administrators, and how the laboratory animal became a standard against which a food policy could be measured. Modern nutrition explains the result: gelatin is a protein, but an incomplete one, lacking the essential amino acid tryptophan and low in several others, so it cannot by itself support growth.

Back to Table of Contents

8. An Early Description of Anaphylaxis, 1839

In 1902 the French physiologist Charles Richet and his colleague Paul Portier described a startling reaction: animals that had tolerated a first injection of a foreign substance could die of shock after a second, small dose. Richet named it anaphylaxis and received the 1913 Nobel Prize for the work.

Historians of allergy credit Magendie with an early description of the same phenomenon more than sixty years before. The episode usually recounted, discussed by Saavedra-Delgado in 1991 under the title “François Magendie on anaphylaxis (1839)”, involves rabbits given repeated injections of egg albumin, which died after a later injection. Magendie did not build a theory on the observation, and the idea of the immune system as a source of harm had to wait for Richet. The story of what Richet found, and the modern understanding of the reaction, is on the Charles Richet page and the anaphylaxis page.

Back to Table of Contents

9. The Vivisection Controversy

Nearly everything on this page was learned by experiments on living animals, before anaesthesia existed. Magendie made no secret of his methods; he lectured with them. According to the Dictionary of Scientific Biography, the public demonstrations he gave on living dogs during a visit to England in 1824 provoked anti-vivisection campaigns there. The British debate over animal experiments continued for decades and led in 1876 to the first British law regulating them, the Cruelty to Animals Act.

The controversy did not end with the nineteenth century. In 1981, during a debate over proposed limits on animal research in the United States, the psychologist C. R. Gallistel wrote on “Bell, Magendie, and the proposals to restrict the use of animals in neurobehavioral research” in American Psychologist. That piece is one side of a policy argument rather than a historical verdict. The site records the controversy as history: the methods were real, the discoveries were real, and so was the public objection to how they were made.

Back to Table of Contents

10. A Founder of Experimental Pharmacology

How historians describe his method

Magendie announced his programme in a 1809 essay criticising the physiology of Xavier Bichat, arguing that most physiological facts needed to be verified by new experiments. The historian Owsei Temkin (1946) examined the philosophical background of his physiology, and W. R. Albury (1974) analysed the kind of explanation offered in that “manifesto of 1809”. Magendie is often described as an experimentalist who distrusted theory. Park (2025) argues for a more careful picture: Magendie was cautious about his own hypotheses but deliberately designed experiments to test other people’s, such as Bichat’s, and much of his work was collaborative.

His contemporaries saw the same temperament. According to the Dictionary of Scientific Biography, Honoré de Balzac portrayed him in La Peau de chagrin (1831) as the sceptical “docteur Maugredie”, a man who believed only in the scalpel.

Where he was wrong

The Dictionary of Scientific Biography also records his misjudgements. He held that cholera and yellow fever were not contagious and opposed quarantine, and in 1847 he opposed the new ether anaesthesia. Yet the same source notes that he showed experimentally that the saliva of a rabid dog carries a contagious principle.

His place in pharmacology

Grmek wrote that the 1809 poison experiments mark the beginning of modern pharmacology: for the first time, drugs from different plants that produced similar effects were compared by experiment, and the effect was traced to a site in the body. Magendie argued that the action of a medicinal plant depends on chemical substances inside it that can be obtained pure, and the Formulaire of 1821 put the newly isolated alkaloids — strychnine, morphine, quinine, emetine and others — into the hands of physicians, with their effects tested first on animals. The French historian Paul Mazliak (2013) titled his account of Magendie “creator of pharmacology, inspirer of Claude Bernard’s researches”, and Tubbs and colleagues (2008) describe his contributions to pharmacology alongside neuroanatomy and physiology.

The two halves of that description belong together. The man who isolated emetine from ipecacuanha root and traced nux vomica’s action to the spinal cord trained the man who traced curare’s action to the nerve–muscle junction. Bernard’s own Introduction to the Study of Experimental Medicine (1865) — discussed on the Claude Bernard legacy page — turned Magendie’s working habits into a method that medicine still uses.

Back to Table of Contents

Key Research Papers

  1. Bloch H. Francois Magendie, Claude Bernard, and the interrelation of science, history, and philosophy. South Med J. 1989;82(10):1259-61. PubMed PMID: 2678501
  2. Grmek MD. [Unpublished notes of Claude Bernard on the physiologic properties of arrow poisons (curare, upas, strychnine and others)]. Biol Med (Paris). 1966;55:Suppl:i-clix. PubMed PMID: 4222865
  3. Mazliak P. [Medical recollections. François Magendie, creator of the pharmacology, inspirer of Claude Bernard's researches]. Rev Prat. 2013;63(7):1030-3. PubMed PMID: 24167908
  4. Mazliak P. Magendie élucide les fonctions des deux racines des nerfs rachidiens. BibNum. 2023. DOI: 10.4000/bibnum.605
  5. Rice G. The Bell-Magendie-Walker controversy. Med Hist. 1987;31(2):190-200. PubMed PMID: 3550329
  6. Jørgensen CB. Aspects of the history of the nerves: Bell's theory, the Bell-Magendie law and controversy, and two forgotten works by P.W. Lund and D.F. Eschricht. J Hist Neurosci. 2003;12(3):229-49. PubMed PMID: 14628540
  7. Drouin E, Kwiatkowski A, Hautecoeur P. The Bell-Magendie debate. Lancet Neurol. 2022;21(2):121. PubMed PMID: 35065034
  8. Tubbs RS, Loukas M, Shoja MM, Shokouhi G, Oakes WJ. François Magendie (1783-1855) and his contributions to the foundations of neuroscience and neurosurgery. J Neurosurg. 2008;108(5):1038-42. PubMed PMID: 18447728
  9. Sourkes TL. Magendie and the chemists: the earliest chemical analyses of the cerebrospinal fluid. J Hist Neurosci. 2002;11(1):2-10. PubMed PMID: 12012572
  10. Lanska DJ. Chapter 29: historical aspects of the major neurological vitamin deficiency disorders: overview and fat-soluble vitamin A. Handb Clin Neurol. 2010;95:435-44. PubMed PMID: 19892132
  11. McCay CM. Was Magendie the first student of vitamins? Science. 1930;71(1838):315. PubMed PMID: 17779301
  12. Fenton PF. Francois Magendie (October 6, 1783-October 7, 1855). J Nutr. 1951;43(1):3-15. PubMed PMID: 14851024
  13. Stahnisch F. [Standardising hunger: François Magendie's feeding experiments on a gelatin fare 1831-1841]. Medizinhist J. 2004;39(2-3):103-34. PubMed PMID: 15497479
  14. Saavedra-Delgado AM. François Magendie on anaphylaxis (1839). Allergy Proc. 1991;12(5):355-6. PubMed PMID: 1959774
  15. Gallistel CR. Bell, Magendie, and the proposals to restrict the use of animals in neurobehavioral research. Am Psychol. 1981;36(4):357-60. PubMed PMID: 7023302
  16. Temkin O. The philosophical background of Magendie's physiology. Bull Hist Med. 1946;20(1):10-35. PubMed PMID: 20277433
  17. Albury WR. Physiological explanation in Magendie's manifesto of 1809. Bull Hist Med. 1974;48(1):90-9. PubMed PMID: 4608397
  18. Park C. An Experimentalist Who Shunned Hypotheses? A Study of François Magendie's Experimental Medicine. Uisahak. 2025;34(1):279-314. PubMed PMID: 40443274

PubMed Topic Searches

  1. PubMed: Bell–Magendie law
  2. PubMed: Magendie and Claude Bernard
  3. PubMed: Magendie and cerebrospinal fluid
  4. PubMed: Magendie history

Further Reading

Back to Table of Contents

Connections

Back to Table of Contents