HELMONT, JEAN BAPTISTE VAN Bel gian chemist, physiologist and physician, was born at Brussels in 1577. (An alternative date for his birth is 1579 and for his death 1635; see Bull. Roy. Aced. Belg., 1907.) He was educated at Louvain, and, after ranging from one science to another, turned to medicine, in which he took his doctor's degree in 1599• In 1609 he settled at Vilvorde, near Brussels, where he occupied himself with chemical experiments and medical practice until his death on Dec. 3o, Van Helmont presents curious contradictions. On the one hand he was a mystic with strong leanings to the supernatural, an alchemist who believed in the philosopher's stone; on the other hand he was touched with the new learning of Harvey, Galileo and Bacon, and was a careful observer and an exact experimenter. He was the first to understand that there are gases distinct in kind from atmospheric air. The very word "gas" he claims as his own invention, and he perceived that his "gas sylvestre" (carbon di oxide) given off by burning charcoal is the same as that produced by fermenting must. Van Helmont believed that water was the chief, if not the only ultimate constituent of all matter. He showed that plants could grow even though they received nothing but pure water, and so he argued that the wood, bark and roots had been formed from water alone. Van Helmont considered that di gestion, nutrition and even movement are due to ferments, which convert dead food into living flesh in six stages. But having got so far with the application of chemical principles to physiological problems, he introduces a complicated system of supernatural agencies like the archei of Paracelsus, which preside over and direct the affairs of the body. At the same time chemical principles guided him in the choice of medicines—undue acidity of the diges tive juices, for example, was to be corrected by alkalies and vice versa; he was thus a forerunner of the iatrochemical school.
His works were collected and published at Amsterdam as Ortus medicinae, vel opera et opuscula omnia in i668 by his son Franz Mer curius (b. 1618 at Vilvorde, d. 1699 at Berlin), in whose own writings, e.g., Cabbalah Denudata (1677) and Opuscula philosophica (169o), mystical theosophy and alchemy appear in still wilder See also M. Foster, Lectures on the History of Physiology (19o1) ; also Chevreul in Journ. des savants (Feb. and March 185o), and Cap in Journ. pharm. chine. (1852) . Other authorities are Poultier d'El moth, Memoire sur J. B. van Helmont (1817) ; Rixner and Sieber, Beitrage zur Geschichte der Physiologie (1819-26), vol. ii.; Spiers, Helmont's System der Medicin (1840) ; Melsens, Lecons sur van Helmont (1848) ; Rommelaere, Etudes sur J. B. van Helmont (186o) .