To BASIL VALENTINE we are moreover indebted for the discovery of the _Volatile Alkali_, and of its preparation from _Sal Ammoniac_; he also first used mineral acids as solvents, and noticed the production of _Ether_ from Alcohol; he seems also to have understood the virtues of _sulphate of iron_, for he says, when internally administered, it is tonic and comforting to a weak stomach, and that externally applied, it is astringent and styptic: he moreover recommended a _fixed alkali_ made from vine twigs cut in the beginning of March, for the cure of gout and gravel. In the year 1493, was born near Zurich in Switzerland, PARACELSUS, or as he termed himself, Philippus, Theophrastus, Bombastus, Paracelsus de Hohenheim, a man who was destined to produce a greater revolution in the Materia Medica, and a greater change in medical opinions and practice, than any person who had appeared since the days of Galen. He travelled all over the Continent of Europe to obtain knowledge in Chemistry and Physic, and was a great admirer of Basil Valentine, declaring that Antimony was not to be equalled for medicinal virtue, by any other substance in nature: this opinion however does not deserve our respect, for it was not founded upon observation and experiment, but on a fanciful analogy, derived from a property which this metal possesses of refining gold, as I have before related. He also used _Mercury_ without reserve, and appears to have been the first who ventured to administer it internally,[105] for although Avicenna asserts that it was not so poisonous as the ancients had imagined, yet he does not attribute to it any virtues; he merely says, “Argentum quidem vivum, plurimi qui bibunt, _non læduntur_ eo.” Its effects, when applied externally, were well known to Theodoric the friar, afterwards Bishop of Cervia, in the twelfth century, who describes the salivation which mercurial frictions will produce. Paracelsus, moreover, employed Lead internally in fevers,—“_Saturnus purgat febres_” was one of his most favourite maxims. He also gives us directions for the preparation of _Red Precipitate_ with _Mercury_ and _Aqua fortis_.