Today's Google Doodle celebrates the 287th birthday of Jan Ingenhousz, the scientist who discovered photosynthesis.
Despite making one of the most important botanical discoveries in history, Ingenhousz was actually doctor, not a botanist. His specialty was inoculation. Born and educated in the Netherlands, he traveled to England in 1764 specifically to learn the technique from a physician and long-time family friend named John Pringle. By 1767 he had gotten the hang of it; in an effort to control a smallpox outbreak in the village of Hertfordshire, Ingenhousz inoculated about 700 people.
That Herculean effort attracted the attention of Empress Maria Theresa of Austria. Inoculation was a controversial practice at the time, and the medical community in Austria was firmly opposed. The Empress, however, stubbornly (and wisely) wanted the royal family inoculated. In 1768, she summoned Ingenhousz to Vienna to do the job, and that gig led to a cushy full-time spot as the royal physician to the Habsburg family.
Perhaps that gave him time to broaden his curiosity. While in Vienna, Ingenhousz studied electricity and other topics in physics and chemistry, which had fascinated him since his days as a student at the University of Leiden, where he attended lectures on electricity in his spare time (a shocking hobby, no doubt). On a 1771 trip to England, Ingenhousz's formidable curiosity found a new target: plants.
Ingenhousz, along with Benjamin Franklin and a few other traveling companions (the conversation on that journey must have been fascinating) paid a visit to scientist Joseph Priestly, who had recently discovered that plant leaves absorb and emit gases. That exchange led Ingenhousz to eventually discover the chemistry that forms the foundation of nearly every food chain on Earth: photosynthesis.
During photosynthesis, cells in plants' leaves use energy from sunlight to convert carbon dioxide into sugars that the plant can store and break down for energy. Oxygen is a by-product of that process, which is wonderfully convenient for anyone who enjoys breathing. Ingenhousz discovered photosynthesis by making one simple but important observation: in sunlight, leaves emit oxygen, but in the dark, they emit carbon dioxide.
Ingenhousz published his groundbreaking paper in 1779. He lived and worked for another 20 years before passing away in 1799.
