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Jan Ingenhousz Google Doodle: What Did the Dutch Scientist Discover?

Jan Ingenhousz Google Doodle: What Did the Dutch Scientist Discover?

Who does today's Google Doodle honor? Geerdt Mageils put it best in his paper for the 1st Conference of the European Philosophy of Science Association, when he said, "Who discovered photosynthesis? Not many people know. Jan Ingenhousz' name has been forgotten, his life and work have disappeared in the mists of time. Still, the tale of his scientific endeavor show science in action."

Jan Ingenhousz was the Dutch physiologist best known for discovering photosynthesis. His work extends far beyond plant and animal research, though. Ingenhousz is also recognized for inoculating family members of the House of Habsburg against smallpox in 1968. According to Geerdt Magiels, he received many rewards for the inoculation, including gifts and a life-long annual income.

He Inoculated Austrian Royalty Against Smallpox in the 1760s

At age 16, the physician, chemist and engineer began to study medicine at the University of Leuven—as he was Catholic, he could not study at Protestant universities like Leyden or Amsterdam. Ingenhousz went on to receive his MD degree in 1753. Two years later, he started his own medical practice in his hometown of Breda, the Netherlands.

A man of many talents, Ingenhousz created an apparatus that generated electricity in 1766. In 1768, he made his way to Vienna, where he successfully inoculated the family of Empress Maria Theresa, and less than two decades later, he became the first to quantitatively measure heat conduction in metal rods.

It wasn't until about a decade after that triumph that Ingenhousz published his results on plant physiology in a book titled, Experiments Upon Vegetables, Discovering Their Great Power of Purifying the Common Air in Sunshine, and of Injuring It in the Shade and at Night. In the book, he expanded on Joseph Priestley's previous plant research by showing that light is necessary for photosynthesis, only green plants perform it, and that the extent that air will be restored in a green plant exceeds its damaging effect.

According to, the book was translated into a number of languages and became the foundation for related research and understanding the process of photosynthesis.

He Was Interested in Electricity and Heat Conduction

In the words of Magiels, Ingenhousz was a man of the Enlightenment, interested in all facets of science. Fascinated specifically by heat conductivity and the study of electricity, he kept in close contact with Benjamin Franklin and Henry Cavendish.

Illness eventually made study and research difficult for the scientist. Though he was plagued with gall and bladder stones, he spent his later years writing and conducting experiments. He passed away in England in 1799.