Jan Baptist van Helmont, Flemish chemist, physiologist, and physician (born 1577)

Jan Baptist van Helmont was a chemist, physiologist, and physician from Brussels. He worked during the years just after Paracelsus and the rise of iatrochemistry, and is sometimes considered to be "the founder of pneumatic chemistry". Van Helmont is remembered today largely for his 5-year willow tree experiment, his introduction of the word "gas" into the vocabulary of science, and his ideas on spontaneous generation.