Ernst Viktor von Leyden
Leyden studied medicine at the Friedrich-Wilhelms-Institut in Berlin, and was a pupil of Johann Lukas Schönlein (1793–1864) and Ludwig Traube (1818–1876). He was a medical professor at several universities, including Königsberg, Strassburg and Berlin. Leyden was an important influence to the career of Ludwig Edinger (1855–1918), and during his tenure at the University of Königsberg worked closely with Otto Spiegelberg (1830–1881) and Friedrich Daniel von Recklinghausen (1833–1910). Among his better known students and assistants were Hermann Nothnagel (1841-1905) at Königsberg and Hermann Ludwig Eichhorst (1849-1921) in Berlin.
In the 1890s (from 1894) he was a physician to Czar Alexander III of Russia.
Leyden specialized in neurological diseases, and was a leader in establishing proper hospital facilities for tuberculosis patients. He wrote articles on a wide array of medical topics, including works on tabes dorsalis and poliomyelitis. In 1899 he published the two-volume Handbuch der Ernährungstherapie (Textbook of Dietetic Therapy).
Eponymous medical terms named for Ernst von Leyden 
- Charcot-Leyden crystals: colorless crystals found in the sputum of asthma patients, or in the faecal matter of amoebic and ulcerative colitis; named along with neurologist Jean-Martin Charcot (1825-1893).
- Leyden's neuritis: A neuritis in which nerve fibres are replaced by fatty tissue.
- Leyden's paralysis II: A fatal form of paralysis of the extremities that follows epileptiform seizures; seen in patients with hemorrhage of the pons and medulla oblongata.
- Leyden-Möbius syndrome: Pelvic muscular dystrophy; named along with neurologist Paul Julius Möbius (1853-1907).
- Westphal-Leyden ataxia: Acute ataxia that begins in childhood; named along with neurologist Karl Friedrich Otto Westphal (1833-1890).