Which main ideas did Claude Bernard present in An Introduction to the Study of Experimental Medicine?

In his seminal work, An Introduction to the Study of Experimental Medicine (1865), French physiologist Claude Bernard argued that medicine must be grounded in experimental physiology to advance.1

His core arguments included:

• Scientific Foundation: While physical and chemical sciences provide the necessary foundation for physiology, the latter is not entirely reducible to them.1
• Mechanistic Determination: Biology relies on the recognition that life processes are mechanistically determined by physico-chemical forces, rejecting the notion of a "vital force" as an explanation for life.1
• Experimental Rigor: He emphasized the necessity of a guiding hypothesis that must be either confirmed or refuted by experimental results, moving beyond purely empirical observation.1
• Methodology: He asserted that vivisection is indispensable for physiological research.1
• Internal Environment: He introduced the concept of the milieu intérieur, or "internal environment," which describes how organisms maintain stability, a precursor to the modern understanding of homeostasis.12