Sigwart, _Kleine Schriften_, vol. i. p. 1 seq.) made the mixture still worse by the addition of the magic art. The impulse of the modern spirit to subdue nature is here already apparent, only that it shows inexperience in the selection of its instruments; before long, however, nature will willingly unveil to observation and calm reflection the secrets which she does not yield to the compulsion of magic. [Footnote 1: Pletho died at an advanced age in 1450. His chief work, the [Greek: Nomoi], was given to the flames by his Aristotelian opponent, Georgius Scholarius, surnamed Gennadius, Patriarch of Constantinople. Portions of it only, which had previously become known, have been preserved. On Pletho's life and teachings, cf. Fritz Schultze, _G.G. Plethon_, Jena, 1874.] A similar romantic figure was Phillipus Aureolus Theophrastus Bombast Paracelsus[1] von Hohenheim (1493-1541), a traveled Swiss, who endeavored to reform medicine from the standpoint of chemistry. Philosophy for Paracelsus is knowledge of nature, in which observation and thought must co-operate; speculation apart from experience and worship of the paper-wisdom of the ancients lead to no result. The world is a living whole, which, like man, the microcosm, in whom the whole content of the macrocosm is concentrated as in an extract, runs its life course. Originally all things were promiscuously intermingled in a unity, the God-created _prima materia_, as though inclosed in a germ, whence the manifold, with its various forms and colors, proceeded by separation. The development then proceeds in such a way that in each genus that is perfected which is posited therein, and does not cease until, at the last day, all that is possible in nature and history shall have fulfilled itself. But the one indwelling life of nature lives in all the manifold forms; the same laws rule in the human body as in the universe; that which works secretly in the former lies open to the view in the latter, and the world gives the clew to the knowledge of man. Natural becoming is brought about by the chemical separation and coming together of substances; the ultimate constituents revealed by analysis are the three fundamental substances or primitive essences, quicksilver, sulphur, and salt, by which, however, something more principiant is understood than the empirical substances bearing these names: _mercurius_ means that which makes bodies liquid, _sulfur_, that which makes them combustible, _sal_, that which makes them fixed and rigid. From these are compounded the four elements, each of which is ruled by elemental spirits--earth by gnomes or pygmies, water by undines or nymphs, air by sylphs, fire by salamanders (cf. with this, and with Paracelsus's theory of the world as a whole, Faust's two monologues in Goethe's drama); which are to be understood as forces or sublimated substances, not as personal, demoniacal beings. To each individual being there is ascribed a vital principle, the _Archeus_, an