Figure 1. Portrait of Franz Leydig (1821-1908) in his later years, from a painting that has hung in the library of the Institute of Anatomy at the University of Bonn since the days when Leydig was professor there (1875-1887).

[A Kodachrome slide of this lovely painting was kindly provided by Professor H. Egge, Dean of the Medical Faculty, University of Bonn, Germany.]

Christensen 1996, "A history of studies on testicular Leydig cells: The first century," in Payne et al, "The Leydig cell."