Jan Ingenhousz is a Dutch scientist from the 18th century. Born on this day in Breda in 1730, he is responsible for discovering photosynthesis.
Ingenhousz had a varied and exciting life. He began studying medicine at 16 before moving to London, where he successfully immunised hundreds of people who were at risk of smallpox.
Hearing of his achievements, the Austrian Empress Maria Theresa called for him to perform the same immunisation process in Vienna. After inoculating the entire Habsburg family, the Empress hired Ingenhousz as the family's doctor.
Ingenhousz had interests far beyond immunisation, however, which ultimately led to his discovery of the photosynthetic process. He was the first person to notice that oxygen was produced by leaves in sunlight, while carbon dioxide was produced in darkness.
Ingenhousz published his findings in 1799, which has gone on to influence plant life research to this day.