Dirk Barend Kagenaar (1842-1924) started his career as an amanuensis (technical assistant) at the Physiology Laboratory of Utrecht University. His tutor was Professor Harting. When he was no longer an apprentice, he worked together with Professor F.C. Donders. The two designed and made several different instruments. In 1860 he started a factory and store, where he sold not only instruments made in his own factory, but also several instruments produced in foreign factories. The company made and sold physiological, ophthalmological, physical and medical instruments. Almost half of the production was exported. Eventually, his son Lodewijk Barend took over the company. After his death, the company was disincorporated.