A historical review of olfactometry

This article reviews the history of olfactometry from the nineteenth century to the present day. The olfactometer was invented by the Dutch physiologist Hendrik Zwaardemaker (1857–1930), whose work we describe in detail here, in 1888. Since then, his instrument has been used by many European and American physiologists and psychologists. The French scientific community, however, was reluctant to use the new Zwaardemaker device, and the psycho-physiologist Charles Henry (1859–1926) therefore made his own olfactometer. As Jacques Passy (1864–1898) considered Henry’s apparatus unsuitable for measuring perceptual odor thresholds, he developed a new measurement technique that was adopted by many researchers after him. The invention in 1904 of the osmi-esthesiometer by Edouard Toulouse and Nicolae Vaschide derived directly from the experimental work carried out by Passy during the 1890s. Today, the evaluation of olfactory performance still requires the use of olfactometry, from simple forms (olfactory test using jars) to more complex apparatus (sending odorants to the nose). The Zwaardemaker olfactometer is no longer used, but many instruments or methods stem from this early invention.