Otto Wallach was a highly regarded professor of chemistry whose curiosity about essential oils led to research that benefited both organic chemistry and an important industry. For his meticulous procedures and initiative in the study of terpenes, a class of compounds he identified and named as essential oils, Wallach received the Nobel Prize in chemistry in 1910. Essential oils, called ethereal oils in Wallach's time, are fragrant extracts from plant materials that are used in perfumes, flavorings, and medicines. Terpenes are responsible for much of the pleasant odor associated with essential oils. Wallach's work provided a scientific foundation for the fragrance industry.

Otto Wallach was born on March 27, 1847, in Königsberg, in East Prussia (Königsberg is now called Kaliningrad and is part of the reorganized former Soviet Union). Wallach's mother was Otillia Thoma Wallach; his father, Gerhard Wallach, was an official in the Prussian government whose...