Polyneuritis in Oppenheim's Lehrbuch, 1894-1923: Terminological stability amid etiological expansion.

The substitution of polyneuropathy for polyneuritis renamed an entire category of peripheral-nerve disease, yet the moment of exchange has never been dated against the successive editions of a single authority. This study tests terminological continuity within the seven editions of Hermann Oppenheim's influential Lehrbuch der Nervenkrankheiten (1894-1923). Repository optical character recognition (OCR; ABBYY FineReader) across all 11 physical volumes was searched for Polyneuropath- forms. Seven predefined 49-page windows were separately subjected to repeat OCR as a technical cross-check; the etiological sections and selected passages were checked against facsimiles. Serial comparison of the chapter heading, etiological framing, and pathological description was performed, and the etiological causes named in each edition were coded inductively. No target form was identified in any edition, whereas positive controls were consistently recovered. The chapter heading, core etiological statement, and principal pathological formulation remained stable across all seven editions. The source matrix shows that the catalog of named etiological entries expanded from 31 to 54, while the clinicopathological framework persisted unchanged. A direct title-level contrast appears in English by 1938. Polyneuritis remained a durable clinicopathological umbrella whose etiological range could grow without lexical replacement. The findings support non-adoption of Polyneuropathie within this textbook tradition through 1923 and document terminological inertia as a form of epistemic conservatism.