Jan Baptista Van Helmont,'a Flemish physician, born in Brussels in 1577, died near Vil-voorden, Dec. 30, 1644. He was educated at the university of Louvain with a view to the church, but refused to take orders, and spent several years in the universities of Italy and France, studying chemistry, natural philosophy, and medicine. On returning home he settled upon his estate near Vilvoorden. Dissatisfied with the works of Hippocrates, Galen, and Paracelsus, he attempted a reform in medicine. His system is mingled with considerable mysticism, but he did much to introduce exactness into science. He was the first to apply the term gas to the elastic fluids which resemble air in physical properties. His gas sylvestre was what is now known as carbonic acid, for, he says, it is evolved during the fermentation of wine and beer, and when charcoal is burned in the air, and also when carbonate of lime is dissolved in vinegar or nitric acid. To the combustible gases found in the intestines he gave the names gas pingue, gas siccum, and gas fulginosum. He had no accurate knowledge of the gases which he produced or examined, but made the important discovery that air diminishes in bulk when bodies are burned in it.

He believed that respiration consisted in the drawing of air into the pulmonary arteries and veins, which caused a fermentation necessary for its revivification. He believed with Paracelsus in the existence of an archoeus, or spiritual essence or power which presided over digestion and fermentation. Water he considered capable of furnishing all the material of plants, and ultimately of fish and other animals, and also that it produced elementary earth or pure quartz, and the chemical principles salt, sulphur, and mercury. He excludes fire from the number of the elements because it is not a substance. The archaeus has the power to draw all bodies from water where a ferment exists. This ferment preexists in the seed which is developed by it. The ferment expels an odor which attracts the generating spirit of the archaeus. This spirit consists of an aura vitalis, which forms matter after its own idea. In man the seat of the archaeus is in the stomach, and it presides also over the spleen; and in consequence of its influence man is much nearer to the realm of spirits than to the earth. As all diseases were in his opinion caused by the ar-chaeus, his treatment consisted in calming it, relying upon dietetics and the imagination of his patients.

Mercurials, antimonials, opium, and wine he believed to be agreeable to the archaeus. His preference for chemical remedies raised chemistry to a higher rank in the opinion of the medical men of his time. On account of the extraordinary cures that he was believed to have made, he is said to have been arrested as a sorcerer. The most important of his works is his Ortus Medicinoe, id est Initia Physical inaudita, Progressus Medicinoe no-vus in Morborum ultionem ad Vitam longam, which was published by his son four years after his death, and translated into Dutch, French, German, and English. A volume of translations of some of his works was published by W. Charlton in 1650, entitled "The Ternary of Paradoxes," " The Magnetic Cure of Wounds," "The Nativity of Tartar of Wine," and "The Image of God in Man."