| Jan Ingenhousz | |
|---|---|
Jan Ingenhousz
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| Born | December 8, 1730 Breda |
| Died | September 7, 1799 Calne |
| Residence | Breda, London, Vienna, Calne |
| Nationality | Dutch |
| Fields | Physiology |
| Alma mater | Catholic University of Leuven |
| Known for | Photosynthesis |
| Influences | Pieter van Musschenbroek David Gaub |
Jan Ingenhousz or Ingen-Housz FRS (December 8, 1730 – September 7, 1799) was a Dutch physiologist, biologist and chemist. He is best known for showing that light is essential to photosynthesis and thus having discovered photosynthesis.[1] [2][3] He also discovered that plants, like animals, have cellular respiration.[4] He went to England in 1764 and in a few months he had inoculated over 700 people. The British King George III(1738-1820) sent Ingenhousz to Austria to inoculate the Austrian Royal Family. He had planned to inoculate the Royal Family by pricking them with a needle and thread that were coated with smallpox germs taken from the pus of a smallpox-infected person. The idea of the inoculation was that by giving a few germs to a healthy body the body would develop immunisation from smallpox. The inoculation was a success. He also successfully inoculated the members of the Habsburg family in Vienna against smallpox in 1768 and subsequently became the private counsellor and personal physician to the Austrian Empress Maria Theresa. [5]
In the 1770's Ingenhousz became interested in gaseous exchanges of plants prior to reading about the work of scientist Joseph Priestly (1733-1804),who found out that plants make and absorb gases.In 1779, Ingenhousz discovered that, in the presence of light, plants give off bubbles from their green parts while, in the shade, the bubbles eventually stop.[6] He identified the gas as oxygen. He also discovered that, in the dark, plants give off carbon dioxide. He realized as well that the amount of oxygen given off in the light is more than the amount of carbon dioxide given off in the dark. This demonstrated that some of the mass of plants comes from the air, and not only the soil.
In addition to his work in the Netherlands and Vienna, Ingenhousz spent time in France, England, Scotland, and Switzerland, among other places. He carried out research in electricity, heat conduction, and chemistry, and met and corresponded with both Benjamin Franklin and Henry Cavendish.[7] In 1785, he described the irregular movement of coal dust on the surface of alcohol and therefore has a claim as discoverer of what came to be known as Brownian motion. Ingenhousz was elected a Fellow of the Royal Society of London in 1779.
In 1799, Ingenhousz died in, and was buried at, Calne, England. His wife died the following year.[8]