Although German physician Robert J. Feulgen published seventy research papers about the chemistry of physiology, histochemistry, and wrote a review of nucleic acid chemistry titled Chemie und Physiologie der Nucleinstoffe (Chemistry and Physiology of Nucleic Acids), he is best known for his discovery of a method for staining nucleic acid, now termed a Feulgen reaction.

Feulgen was born in Werden, Germany, into a working class family, Feulgen paved his way to the medical school through an outstanding student performance that opened to him the doors of the University of Freiburg at Breisgau in 1905. His medical residency was taken in the City Hospital of Kiel, where he wrote his dissertation on the purine metabolism of patients with chronic gout. After finishing residence, he moved to Berlin and started his carrier as an experimental researcher at the Chemistry Department of the Physiological Institute, then under the direction of Hermann Steudel...