all manner of eccentric beliefs (including the efficacy of spirits and demons in pathological cases), a drunkard, a wastrel, an evil liver, a practiser of necromancy, an astrologer, a magician, an atheist, an alchemist--indeed an “ist” of all defamatory kinds within the terminology of the sixteenth century and of all disputatious churchmen and scientists who have not agreed with his theories and conclusions ever since. Let us begin with the facts of his life. His name was Theophrastus Bombast von Hohenheim, and he was the son of a doctor living in Einsiedeln in the canton of Schwyz, named Wilhelm Bombast von Hohenheim, natural son of a Grand Master of the Teutonic Order. He was born in 1490. It was not uncommon for a man of that age who was striving to make a name for himself, to assume some _nom de plume_ or _de guerre_; and with such a family record as his own, it was no wonder that on the threshold of his life the young Theophrastus did so. In the light of his later achievements, we can well imagine that he had some definite purpose in mind, or at least some guiding principle of suggestiveness, in choosing such a compound word from the Greek as Paracelsus (which is derived from “para,” meaning before, in the sense of superior to, and Celsus, the name of an Epicurean philosopher of the second century.) Celsus appears to have had views of great enlightenment according to the thought of his own time. Unhappily only fragments of his work remain, but as he was a follower of Epicurus after an interval of between four and five centuries, it is possible to get some idea of his main propositions. Like Epicurus he stood for nature. He did not believe in fatalism, but he did in a supreme power. He was a Platonist and held that there was no truth which was against nature. It is easy to see from his life and work that Theophrastus Bombast von Hohenheim shared his views. His intellectual attitude was that of a true scientist--denying nothing _prima facie_ but investigating all. “There lives more faith in honest doubt, Believe me, than in half the creeds.” His father moved in 1502 to Villach in Carinthia, where he practised medicine till his death in 1534. Theophrastus was a precocious boy; after youthful study with his father, he entered the University of Basel when he was about sixteen, after which he prosecuted chemical researches under the learned Trithemius Bishop of Sponheim who had written on the subject of the Great elixir--the common subject of the scientists of that day,--and at Wurzburg. From thence he proceeded to the great mines in the Tyrol, then belonging to the Fugger family. Here he studied geology and its kindred branches of learning--especially those dealing with effects and so far as possible with causes--metallurgy, mineral waters, and the diseases of and accidents to mines and miners. The theory of knowledge which he deduced from these studies was that we must learn nature from nature.