Claude Bernard

Claude Bernard ( born July 12, 1813 in Saint -Julien in the Rhône department, † February 10, 1878 in Paris) was a French physician and physiologist.

He discovered the role of pancreatic secretion in the digestion of fats, the role of the liver in the internal secretion of glucose in the blood, which one was the cause of diabetes on the track. He also showed how carbon monoxide blocks the breathing.


Claude Bernard was born in Saint Julien (specifically in the town of Chatenay ) in the Beaujolais, the son of Pierre François Bernard ( † 1847), a wine grower and teacher, and Jeanne Saulnier († 1867). He was the eldest son of this family of four. The village priest taught him the basic skills in reading and writing.

Bernard first attended the Jesuit school in Villefranche -sur- Saone, then he became a student at the Collège de Thoissey. At the age of eighteen he had to leave for financial reasons the school. In order to support his father, he took a job as a pharmacist apprentice. From 1832 to 1833 he worked as a pharmacist 's apprentice in Vaise, a suburb of Lyon, works. In 1834 he traveled to Paris. Before studying medicine, the now twenty -year-old busy with the writing. He wrote, inter alia, the play La Rose du Rhône, which was performed in Lyon. Another work, the ( historical ) drama Arthur de Bretagne, he put before the literary critic Saint -Marc Girardin. However, this was not particularly touched by the piece and C. Bernard advised not to want to make the writing to his day job.

1834 Bernard moved to Paris. Here he acquired the baccalaureate and enrolled at the Medical Faculty of the University of Paris. 1843 Bernard received the license. The subject of his 1844 published in the Medical Faculty of Paris thesis was Des matières chez l' homme colorantes. In 1848 he became assistant to François Magendie at the Hôtel- Dieu in Paris. With his work Recherches sur une nouvelle fonction du foie considere comme organs producteur de matière chez l' homme et les sucrée animaux he in 1853 received his doctorate in zoology specialist. In 1854 a Department of General Physiology at the Sorbonne was created for Bernard. In 1855, he was the successor of Magendie at the Collège de France.

On May 7, 1845 married Bernard Marie -Françoise Martin. Your dowry financed part of his research. The couple had two daughters, Jeanne- Antoinette Henriette (1847-1923) and Marie -Louise - Alphonsine Bernard (1850-1922) and the two sons Louis -Henri and Claude -Henri -François Bernard, who at the age of 2 and 15 months died. In the course of the marriage Marie -Françoise developed an aversion to animal experiments, which shifted her husband regularly from the Collège de France in his private laboratory. She tried several times to sabotage attempts and called the ASPCA on to sue her husband. 1869 Bernard entered into a friendly relationship with Madame Marie Raffalovich ( 1832-1921 ), which deepened after his divorce on 22 August 1870. She was the wife of a Parisian banker and was in Bernard's last years of life to a faithful friend.

When Claude Bernard died in 1878, he was given a public funeral. He is buried at the Père Lachaise Cemetery in Paris.

Scientific Work

The research mission of Claude Bernard was - as he himself declared - the use of the scientific method in medicine to establish. He refuted many traditional doctrines, took nothing for granted and relied on animal testing. Unlike most of his contemporaries, he insisted that all living things were placed under the same natural laws as inanimate matter. Bernard explained that facts are the foundation of the sciences and thus analogy thinking and Apriorischlüsse for an exact science are not allowed. Starting point for the research are observations. Explanatory hypotheses have to be verified in the experiment for accuracy. Under the given experimental conditions the same causes would have the same effects, it would be a causal relationship. The physiological laboratory was in his opinion the place of scientific research and knowledge. On the other hand he holds the hospital or the ward for observation fields. The clinic would be only the vestibule of scientific medicine, while the laboratory is the " true sanctuary " medical science. Only there could be by means of the experimental analysis of Pathological not distinguish pathological or explain at best.

The first he described the importance of the milieu intérieur for the maintenance of life and was one of the first protagonists of homeostasis. He developed this concept and the concept Fixité du milieu intérieur, after which the internal fluids are essential to the life of the animals and their survival depends on whether just this homeostasis can be maintained.

" Je crois avoir le premier insisté sur cette idée qu'il ya pour l' animal réellement deux milieux: un milieu extérieur est dans lequel placé l' organisme, et un milieu intérieur dans les éléments of lequel vivent tissus. L' existence de l' être se passe, non pas dans le milieu extérieur, air atmosphérique pour l' être Aérien, eau douce ou pour les animaux salée aquatiques, mais dans le milieu intérieur Formen liquid par le liquid organique circulant qui Entouré et où tous les éléments baignent anatomiques of tissus; c'est la ou le lymph plasma, la partie du sang cash, qui, chez les animaux supérieurs, pénètrent les tissus et l'ensemble de tous les constituent liquides Interstitiels, de toutes les expression nutritions locales, source et de tous les confluent échanges élémentaires "

"I think I have the first highlighted the idea that there are actually two environments are for the animal: an outer environment in which the organism is and an internal environment in which the components of living tissue are located. The actual existence of the being does not happen in the external environment - atmospheric air, fresh or salt water for aquatic animals - but within the liquid medium by circulating organic liquid. Surrounds or encloses all the anatomical elements of the tissue. It is the lymph or plasma fluid, the liquid components of blood in the higher animals, they penetrate into the tissues and form all the interstitial fluids. They are an expression of all the local diet, source and mouth of all elementary exchanges "

In the years 1848-1849 he discovered the function of the pancreatic secretion for fat digestion of the pancreas. In 1853 he earned a doctorate, Recherches sur une nouvelle fonction du foie considere comme organs producteur de matière chez l' homme et les sucré animaux, in Zoology with a large study on the metabolism of the liver and their role in digestive processes. He discovered the glycogen.

Bernard described in 1852, which in mammals occurred warming and increased circulation of the entire head after transection of the cervical sympathetic ganglia. In mammals, there are three cervical ganglia: the upper ( superior cervical ganglion ), the median ( middle cervical ganglion ) which is not constant and the lower cervical ganglion ( inferior cervical ganglion ).

In 1865 C. Bernard appeared most extraordinary book about the philosophy and the basic understanding of experimental medicine. Bernard is also the scientist who founded with his curare experiments on frogs, the discipline of experimental physiology. He was able to show in 1856 that curare blocked the line functions of the neuromuscular synapses.

In 1868 he was admitted to the Académie française, and in the same year, the Royal Swedish Academy of Sciences. The American historian of science I. Bernard Cohen of Harvard University called Claude Bernard " one of the greatest scientists ".

Probably the most famous quote from Claude Bernard, with which he concludes his 40 years of research, is:

" Le n'est rien germe, le terrain est tout! "

" The germ is nothing, the milieu is everything!"

Works (selection)

  • Recherches sur une nouvelle fonction du foie considere comme organs producteur de matière chez l' homme et les sucré animaux. Martinet, Paris 1853
  • Leçons de physiology expérimentale appliquée à la médecine, faites au Collège de France. J.-B. Baillière et fils, Paris 1855-56
  • Introduction à l' étude de la médicine experimental. Paris 1865; dt ed: Introduction to the Study of Experimental Medicine, Leipzig, 1961 ( French text at Project Gutenberg )
  • Leçons de pathology expérimentale et sur ​​les lecons propriétés de la moelle épinière. J.-B. Baillière et fils, Paris, 1872
  • Leçons sur les phénomènes de la vie communs aux animaux et aux végétaux. 2 vols. J.-B. Baillière et fils, Paris 1878-79