This article explores the profound impact of the thought of Claude Bernard (1813-78) and his philosophy of experimentalism elaborated in his masterwork An Introduction to the Study of Experimental Medicine. I argue that Bernard's far-ranging theoretical impact on medicine and biology marks the end of conventional vitalism and the elusive notion of a "vital force" as a legitimate scientific concept. His understanding of medicine is as epistemologically significant in its time as Newton's contribution was to the physical sciences in the seventeenth century. This essay treats Bernard's philosophical ambitions seriously, exploring his important, even central, role in the mental world of nineteenth-century France. This includes his influence on Henri Bergson (1859-1941) and other late-nineteenth century thinkers. The subtext of Bernard's experimental epistemology is also contrasted with a key idealist philosopher of the period, the German Arthur Schopenhauer (1788-1860), and placed in the context of the larger European philosophical sphere. In contrast to much of mid-nineteenth-century philosophy, Bernard, in creating the framework for experimental medicine, argued for an experimental approach in which a priori assumptions were to be strictly constrained. Bernard's thoughts on the nature of experiment put an end to "systems" in medicine, ironically by replacing all previous medical philosophies with the all-embracing "system" of experiment. And yet, while "vital forces" fade after Bernard, a form of vitalism still flourishes. Even in Bernard's own work, in the struggle with concepts like determinism, complexity, and causality, there is a realization of the unique character of living function in a kind of "physical vitalism."