Hendrik Zwaardemaker ( – ) was a Dutch scientist who invented the

olfactometer An olfactometer is an instrument used to detect and measure odor dilution. Olfactometers are used in conjunction with human subjects in laboratory settings, most often in market research, to quantify and qualify human olfaction. Olfactometers are ...

in 1888. From 1897 to 1927 he was professor of Experimental

Physiology Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical ...

at the

University of Utrecht Utrecht University (UU; nl, Universiteit Utrecht, formerly ''Rijksuniversiteit Utrecht'') is a public research university in Utrecht, Netherlands. Established , it is one of the oldest universities in the Netherlands. In 2018, it had an enrollme ...

. In 1903 he became member of the

Royal Netherlands Academy of Arts and Sciences The Royal Netherlands Academy of Arts and Sciences ( nl, Koninklijke Nederlandse Akademie van Wetenschappen, abbreviated: KNAW) is an organization dedicated to the advancement of science and literature in the Netherlands. The academy is housed ...

. In addition to his work on the

sense A sense is a biological system used by an organism for sensation, the process of gathering information about the world through the detection of Stimulus (physiology), stimuli. (For example, in the human body, the brain which is part of the cen ...

of smell, he also conducted research on the human

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...

. He found that salts of

potassium Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosphe ...

and other

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consid ...

elements stimulated the heart. His major work was "Die Physiologie des Geruchs" (Physiologie of Olfaction), it appeared in 1895.

Zwaardemaker Pairs

An important contribution of Zwaardemaker's studies is the concept of odor conjugates. Zwaardemaker discovered that certain odors could be prevented from detection by smell senses when mixed with various

essential oils An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the o ...

. These combination of odors are referred to as Zwaardemaker Pairs, (or Z-pairs).

References

19th-century Dutch inventors Dutch physiologists 1857 births 1930 deaths Members of the Royal Netherlands Academy of Arts and Sciences Scientists from Haarlem Academic staff of Utrecht University 19th-century Dutch scientists 20th-century Dutch scientists {{Netherlands-scientist-stub