Ernst Wilhelm Theodor Trendelenburg (16 July 1877 – 16 March 1946) was a German physiologist known for his work in physiological optics. He studied physiology at the University of Freiburg, receiving his doctorate from the University of Leipzig in 1900. He worked as an assistant to Johannes von Kries at Freiburg and to Ewald Hering at Leipzig. In 1904 he obtained his habilitation for physiology at Freiburg, and in 1911 became a full professor at the University of Innsbruck. Afterwards, he held professorships at the universities of Giessen (from 1916), Tübingen (from 1917) and Berlin (from 1927). In 1931 he became a member of the Prussian Academy of Sciences. He was the son of surgeon Friedrich Trendelenburg and the grandson of renowned philosopher Friedrich Adolf Trendelenburg. He was the brother of pharmacologist Paul Trendelenburg. He was an accomplished musician, being adept at playing violin and cello. It is believed that he was the first scientist to conduct studies on the role of bow pressure, contact point and bow speed in the determination of tone color. During his time spent at the University of Freiburg he conducted studies involving animal psychology that included intelligence testing with monkeys. He is also credited as the inventor of the red adaptation goggles. Source: Wikipedia (en)