Helmont, Jan Baptist van

Flemish chemist and physician. Helmont was the first to realize that there are gases other than air, and established the present scientific sense of the word ‘gas’ (from Greek cháos). He also investigated the chemical properties of the fluids of the human body. His chief work, Ortus medicinae, was published by his son in 1648.

Discoveries
Helmont identified four gases: carbon dioxide, carbon monoxide, nitrous oxide, and methane. He was the first to take the melting point of ice and the boiling point of water as standards for temperature and the first to use the term ‘saturation’ to signify the combination of an acid and a base. In medicine, Helmont used remedies that specifically considered the type of disease, the organ affected, and the causative agent. He demonstrated acid as the digestive agent in the stomach.