improved upon them. His books on topics like botany, zoology, and minerals included information from ancient sources, but also results of his own empirical investigations. These investigations pushed several of the special sciences forward, beyond the reliance on classical texts. In the case of embryology, for example, it has been claimed that little of value was written between Aristotle and Albert, who managed to identify organs within eggs. Furthermore, Albert also effectively invented entire special sciences, where Aristotle has not covered a topic. For example, prior to Albert, there was no systematic study of minerals. For the breadth of these achievements, he was bestowed the name Doctor Universalis. Much of Albert's empirical contributions to the natural sciences have been superseded, but his general approach to science may be surprisingly modern. For example, in De Mineralibus (Book II, Tractate ii, Ch. 1) Albert claims, "For it is [the task] of natural science not simply to accept what we are told but to inquire into the causes of natural things." Alchemy In the centuries since his death, many stories arose about Albert as an alchemist and magician. "Much of the modern confusion results from the fact that later works, particularly the alchemical work known as the Secreta Alberti or the Experimenta Alberti, were falsely attributed to Albertus by their authors to increase the prestige of the text through association." On the subject of alchemy and chemistry, many treatises relating to alchemy have been attributed to him, though in his authentic writings he had little to say on the subject, and then mostly through commentary on Aristotle. For example, in his commentary, De mineralibus, he refers to the power of stones, but does not elaborate on what these powers might be. A wide range of Pseudo-Albertine works dealing with alchemy exist, though, showing the belief developed in the generations following Albert's death that he had mastered alchemy, one of the fundamental sciences of the Middle Ages. These include Metals and Materials; the Secrets of Chemistry; the Origin of Metals; the Origins of Compounds, and a Concordance which is a collection of Observations on the philosopher's stone; and other alchemy-chemistry topics, collected under the name of Theatrum Chemicum. He is credited with the discovery of the element arsenic and experimented with photosensitive chemicals, including silver nitrate. He did believe that stones had occult properties, as he related in his work De mineralibus. However, there