Willibald Nagel

Willibald Nagel (19 June 1870 – 13 November 1911) was a German physiologist, best known for his work in the field of sensory physiology.

Born in Tübingen, Nagel earned doctorates in sciences (1892) and medicine (1893), obtaining his habilitation two years later at the University of Freiburg as an assistant to physiologist Johannes von Kries.

He is best remembered for the development of ophthalmic instruments and aids—he built an adaptometer for measuring dark adaptation of the eyes, an anomaloscope for the study of color blindness, and introduced the so-called Nagelschen Farbtäfelchen (Nagel's color tablet) for the testing of color perception.

[1][2] With Hermann Ebbinghaus, he was co-editor of the journal Zeitschrift für psychologie und physiologie der sinnesorgane.

He was the author of the popular Handbuch der Physiologie des Menschen (Handbook of Human Physiology), published in five volumes from 1904 to 1910.