He received his early education in the Jesuit school of that town, and then proceeded to the college at Lyon, which, however, he soon left to become assistant in a druggist's shop.

[5] His leisure hours were devoted to the composition of a vaudeville comedy, and the success it achieved moved him to attempt a prose drama in five acts, Arthur de Bretagne.

[6] In 1834, at the age of twenty-one, he went to Paris, armed with this play and an introduction to Saint-Marc Girardin, but the critic dissuaded him from adopting literature as a profession, and urged him rather to take up the study of medicine.

[6] In 1845, Bernard married Marie Françoise "Fanny" Martin for convenience; the marriage was arranged by a colleague and her dowry helped finance his experiments.

[7] His field of research was considered inferior at the time, the laboratory assigned to him was simply a "regular cellar.

"[8] Some time previously Bernard had been chosen to be the first occupant of the newly instituted chair of physiology at the Sorbonne, but no laboratory was provided for his use.

It was Louis Napoleon who, after an interview with him in 1864, repaired the deficiency, building a laboratory at the Muséum national d'Histoire naturelle in the Jardin des Plantes.

At the age of 19 Claude Bernard wrote an autobiographical prose play in five acts called Arthur de Bretagne,[9] which was published only after his death.

[9][11] Patron Claude Bernard's aim, as he stated in his own words, was to establish the use of the scientific method in medicine.

Claude Bernard's first important work was on the functions of the pancreas, the juice of which he proved to be of great significance in the process of digestion; this achievement won him the prize for experimental physiology from the French Academy of Sciences.

[12] A second investigation – perhaps his most famous – was on the glycogenic function of the liver;[13] in the course of his study he was led to the conclusion, which throws light on the causation of diabetes mellitus, that the liver, in addition to secreting bile, is the seat of an internal secretion, by which it prepares sugar at the expense of the elements of the blood passing through it.

[2] The study of the physiological action of poisons was also of great interest to him, his attention being devoted in particular to curare and carbon monoxide gas.

Bernard is widely credited with first describing carbon monoxide's affinity for hemoglobin in 1857,[14] although James Watt had drawn similar conclusions about hydrocarbonate's affinity for blood acting as "an antidote to the oxygen" in 1794 prior to the discoveries of carbon monoxide and hemoglobin.

The constancy of the environment presupposes a perfection of the organism such that external variations are at every instant compensated and brought into balance.

In consequence, far from being indifferent to the external world, the higher animal is on the contrary in a close and wise relation with it, so that its equilibrium results from a continuous and delicate compensation established as if the most sensitive of balances.

The physician-scientist George Hoggan spent four months observing and working in Bernard's laboratory and was one of the few contemporary authors to chronicle what went on there.

He was later moved to write that his experiences in Bernard's lab had made him "prepared to see not only science, but even mankind, perish rather than have recourse to such means of saving it.

The "despisers of their fellows" lack the "ardent desire for knowledge" that the true scientific spirit will always have—and so the progress of science will never be stopped by them.