Perfume (UK: /ˈpɜːfjuːm/, US: /pərˈfjuːm/; French: parfum) is a mixture of fragrant essential oils or aroma compounds, fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent. The 1939 Nobel Laureate for Chemistry, Leopold Ružička stated in 1945 that "right from the earliest days of scientific chemistry up to the present time perfumes have substantially contributed to the development of organic chemistry as regards methods, systematicclassification, and theory."