Initially instructed in Latin by the local priest, Bernard later attended a Jesuit-operated school in Villefranche, where a lack of natural science education prevailed. At the age of nineteen, he apprenticed under apothecary Millet in Vaise, Lyons, exposing himself to the empirical nature of pharmacotherapy during that period.
Although Bernard earned a medical degree in Paris on December 7, 1843, he never practiced medicine and held ambivalent sentiments toward physicians. His 1843 doctoral thesis, "Du suc gastrique et de son rôle dans la nutrition," contributed to both medicine and pure science, providing fresh insights into gastric digestion and the transformation of carbohydrates in animals.
Teaming up with François Magendie, a prominent physiologist, Bernard initially worked in Magendie's shadow but soon established his own prominence. In 1854, a chair of general physiology was established for him at the Sorbonne, and he became a member of the Academy of Sciences. After Magendie's demise in 1855, Bernard succeeded him as a full professor and later assumed the chair of experimental medicine at the Collège de France.
A key figure in shaping experimental medicine, Bernard transcended the vitalism and indeterminism of earlier physiologists. His primary contribution lay in the concept of the internal organism environment, laying the groundwork for the contemporary understanding of homeostasis—the self-regulation of vital processes. He illustrated the reversibility of biochemical reactions, such as the conversion of glucose to glycogen. Prior to Bernard, it was established that some organs produced external excretions (urine, bile, sweat, tears). By revealing the liver's secretion of glucose into the blood, he introduced the notion of organs producing and secreting molecules internally, pioneering the concept of internal secretion.
Claude Bernard's Scientific Contributions
