Ingen-Housz, Jan

[eeng genhows] (1730–99) Dutch plant physiologist: early student of photosynthesis.

Ingen-Housz studied physics, chemistry and medicine and researched in all three; his early career was guided by a British army surgeon who met the family when encamped near their home in Breda. He travelled widely in Europe, as a popular and expert user of the pre-Jenner inoculation method (a risky affair, using live virus) against smallpox. He spent his last 20 years in London, where he published his work on gas exchange in plants. He showed that the green parts of plants absorb carbon dioxide and give off oxygen only in the light; in darkness they release carbon dioxide. This process, photosynthesis, is perhaps the most fundamental reaction of living systems, since it is the source of much plant substance, and animal life depends on the life of plants. Ingen-Housz made a number of curious inventions and discoveries. They include: a device for giving oxygen to a patient with chest disease; a pistol which used an explosive mixture of air and diethylether vapour and which was fired electrically; a hydrogen-fuelled lighter to replace the tinderbox; and thin glass microscope cover plates.