French histologist and pathologist whose dynamic approach to the study of minute anatomy made his laboratories a world centre for students of histology and contributed especially to knowledge of nervous structure and function.

Assistant to the eminent French physiologist Claude Bernard (Bernard, Claude) (1867), Ranvier became director of the histology laboratory (1875) at the Collège de France, Paris, where he later was appointed professor of general anatomy (1886). Ranvier is credited with transforming histology from a descriptive discipline into an experimental science that could serve as a basis for physiological observations. He devoted most of his research to elaborating detailed nerve and skin structure. In 1878 he described constrictions seen in certain nerve fibres, now known as the nodes of Ranvier, where discontinuities occur in the nerve's myelin coating, and discovered nerve terminals between the epithelial cells of the tongue that are now known as Ranvier's tactile disks. With the French bacteriologist André-Victor Cornil he wrote Manual of Pathological Histology (1869), considered a landmark of 19th-century medicine.