(1580) Flemish chemist, physiologist, and physician Jan Baptist van Helmont is born. He is known for proposing the idea that digestion requires chemicals in the stomach, not heat as was previously thought.
(1896) American psychologist David Wechsler is born. He is known for developing a number of intelligence tests, including the Wechsler Adult Intelligence Scale.
(1899) Swiss chemist Paul Hermann Müller is born. He he won the 1948 Nobel Prize in Physiology or Medicine for determining the potential role of DDT in controlling vector diseases like malaria and yellow fever.