HELMONT, JOHN BAPTIST VAN, was born at Brussels iu 1577, the youngest son of a noble family, who derived their name from an estate and castle in Brabant. He has left an account of himself prefixed to his Ortus Medicines, published at Amsterdam in 1615, from which we learn that he was educated at the university of Louvain, and intended for the church ; but was ao dissatisfied with the course of study there that ho refused to take a degree when only seventeen. He says he had studied Euclid and Copernicus, but had no relish for them. lie next tried metaphysics, which suited him as little. At length he applied to the medical sciences, particularly botany and chemistry. He read he says Galen, Hippocrates, Avicenna, and Greek, Arabian, and modern authors, to the number of six hundred, and after ten years study took a medical degree at Louvain ; after which, being then married, he retired to Vilvorde in 1609. There ho employed himself iu chemical investigations, and studied Paracelsus, but says ho found only obscurity and error iu him. His memoir is a curious mixture of devotion and insanity. He had arrived at the conclusion that all his books and his acquired know ledge were a "mass of stuff," and ho prayed for and believed lie had acquired ,spiritual help. He nevertheless effected some remarkable cures, particularly during a season of plague. For these he was arrested by the inquisition as a sorcerer, but successfully cleared himself ; and to avoid a similar inconvenience he removed to Holland. He
has been reckoned among the alchemists, and no doubt many of his experiments were In that direetiou; but he also effected some service in chemistry. It was he who first used the term gas to denote all elastic fluids which differ from atmospheric air ; and he noticed some of the properties of what he called gas sylvestro, or carbonic acid gas. He stated that it is invisible, and fixed in bodice; and he attributed the phenomena of the Grotto del Cane to its presence. He died December 30, 1644. He had published several works in his life-time; among them were 'De Magnetica Vulnerum Naturali et Legitima Curatioue,' 1621; The Ternary of Paradoxes; the Mapetio Cure of Wounds, the Nativity of Tartar in Wino, and the Image of God in Mau,' 4to, translated by W. Charleton in 1650. He likewise left a considerable number of his writings, which he strictly enjoined his son to have published in the state in which he left them. They were issued in folio in 1618, and are a continuous attack on the Galeniste, but of very little value.
Feteems Mkncuaius vex HELMONT, his son, who was born in 1618, • and died iu 1699, was also a physician, and the author of several works, which, like his father's, are more noticeable for their eccentricity than their value.