Vision studies in Germany: Helmholtz versus Hering.
D005858:Germany; D049672:History, 19th Century; D006801:Humans; D009885:Ophthalmology / Q000266:history*; D010827:Physiology / Q000266:history*; D012574:Schools / Q000266:history*; D012586:Science / Q000266:history; D014796:Visual Perception