Claude Bernard was the first to describe the “milieu intérieur.” His publication Lessons of Phenomena of Life in Animals and Plants [7] was one of the most influential advancements in the history physiology, only comparable to breakthroughs such as that of the Noble Prize winner Otto Meyerhof’s Chemical Dynamics of Life Phenomena. Claude Bernard described for the first time the “milieu intérieur.” He wrote: “I think I was the first to express the idea that for animals there are in fact two environments, one milieu which is outside the body and an inner milieu, in which the components of living tissues are embedded. The real existence of the animal doesn’t take place in the external world but inside the liquid medium of circulating organic fluid. This fluid is the expression of all local nutrition and the source and mouth of elementary exchange” [7].
Fig. 7. Claude Bernard statue in the village of St. Julien en Beaujolais (photo Dr. V. Jörgens).
His Home in St. Julien Became a Museum
In 1861 Claude Bernard purchased, for 60,000 francs, the manor house on the hill of Chatenay above Saint Julien, which is located just beside the small house owned by his parents and where he was born. He used to spend August and September every year at this property. He personally supervised the grape harvesting from his own vineyards and the production of his own Beaujolais. He had a laboratory installed, some of the instruments of which can still be seen there, and, even during his holidays, he carried out experiments, sometimes with frogs collected by boys in the neighborhood (Fig. 6). His property and his birthplace became a museum which was recently renovated (www.agglo-villefranche.fr/musee-claude-bernard.html). Once in the lifetime of every diabetologist, it should be an obligation to visit the birthplace of Claude Bernard and the museum, and of course to bring home some “Claude Bernard Wine” from his vineyards – it could certainly inspire diabetes researchers. They should also not miss out on the opportunity to take a picture of the Claude Bernard statue on the square in front of the church in St. Julien (Fig. 7).
An Inspiring Relationship
The lectures of Claude Bernard at the Collège de France were attended by famous people, including the Emperor of Brazil in 1873. Some of them disturbed the scientist, as he once reported himself: “On my right side was a beautiful, dark haired young woman. She was sitting on an elevated seat in the auditorium and therefore I could see her beautiful foot. She was wearing very nicely decorated shoes. On the left foot, the side of the heart, she was wearing a precious anklet with very expensive jewelry embracing the ankle from above. I must confess that this view was breath-taking.” Completely confused, he mixed up “aorta” and “carotis” and forgot half of his lecture.
In 1869 a young Russian lady, Madame Marie Raffalovich, daughter of wealthy Jewish parents from Odessa, attended one of his lectures at the Collège de France. Some days later this young woman asked for a private meeting and was looking for personal information concerning gynecology. Mrs. Raffalovich was 37 years old when she met the 56-year-old Claude Bernard. At the age of 16 years she had married a rich Russian Banker and lived in Paris. She had a university education and had published about the cultural life and scientific events in Paris in St. Petersburg newspapers. She spoke eight languages fluently and helped Claude Bernard to translate German, Italian, English, and Russian publications. Together, they attended cultural events in Paris and she visited him repeatedly in St. Julien, when Claude Bernard was there for the grape harvesting. Claude Bernard wrote numerous letters from Paris and St. Julien to Madame Raffalovic – 488 of his letters have been preserved and some of them published. Her letters to him were burned as per her request, like Madame von Stein’s hundreds of letters she had addressed to Goethe.
Claude Bernard’s Book: Lessons on Diabetes
In 1877, 21 lectures on diabetes given by Claude Bernard at the Collège de France appeared in the book Leçons sur le diabète et la glycogènese animale [8]. Over 381 pages, he describes countless animal experiments and concludes with a chapter in which he critically examines the explanations of the pathogenesis of diabetes mellitus offered at the time by numerous authors. He warns in advance that the remaining ignorance must not simply be filled with assumptions in order to support the various theories of the pathogenesis. He always demanded proof of the hypotheses through experiments. Thanks to Claude Bernard’s work, all researchers agreed that too much glucose is produced by the liver in diabetes. However, the authors were still much divided on how this happens – Claude Bernard was also reluctant to provide a clear-cut explanation. He never treated patients, and in his Leçons sur le diabète there is no proposal of a treatment for diabetes. Nevertheless, Claude Bernard’s contribution to the understanding of metabolism was one of the most outstanding contributions to diabetes research in medical history.
What Is the Legacy of a Genius?
Claude Bernard did not only study metabolism. His research into neurology fills two volumes. He also studied the effects of curare and carbon monoxide, even the sensibility of plants. All his scientific work is discussed in detail in the outstanding biography by Mirko D. Grmek [9]. Gremek reports an anecdote about the question “what remains of the ideas of a researcher?” In a conversation between Pasteur and Claude Bernard, Pasteur said that he had the impression that his research had not been well received by the medical community. Claude Bernard replied: “It is quite the opposite. The physicians have already learned a lot from your research on infections. A cannula was introduced into my bladder by two colleagues, an older one and a younger one. Both of them washed their hands – the younger one before and the older one after the operation.”
The First National Funeral for a Scientist
On February 10, 1878 Claude Bernard died in his apartment at Rue des Ecoles 40 in Paris. His death was probably as a result of renal failure due to pyelonephritis. The following day, by virtue of a proposal by Gambetta, the parliament decided to organize a national funeral at the expense of the state. On Wednesday February 12, 1878, his obituary filled half of the title page of the Le Figaro newspaper. On February 16, an impressive funeral cortege accompanied Claude Bernard to the Père Lachaise cemetery, where his two sons were also buried.
Immediately after his death, his friends and students collected money for a bronze monument in front of the Collège de France. Sadly, the bronze monument was melted during the Nazi occupation, but was replaced after the war with a stone one. Another monument can be found in the Claude Bernard University in Lyon. The city of Villefranche-sur-Saône debated the proposal of creating a monument but finally decided against it – it was mentioned that he, Claude Bernard, had been politically close to the Emperor and that he had been divorced. The European Association for the Study of Diabetes honored Claude Bernard by inaugurating a medal and lecture in his name. The first two winners of this lecture were subsequently awarded with the Nobel Prize in Physiology and Medicine.
References
1Bernard C: De l’origine du sucre dans l’économie animale. Arch Gén Méd 1848;18:303–319.
2Sonolet J: The Claude Bernard Museum. Fondation Marcel Mérieux.