Saffron of Mars (the peroxide) is dead iron. Verdigris is dead copper. Red oxide of mercury is dead mercury. But, he adds, these dead metals can be revivified, “reduced to the metallic state,” are his exact words (and it is to be noted that he was the first chemist to employ the term “reduce” in this sense), by means of coal. Elsewhere he describes digestion as a solution of food; putrefaction as a transmutation. He knew how to separate gold from silver by nitric acid. It is quite certain that the writer of Paracelsus’s works was a singularly observant and intelligent chemist. He had “a wolfish hunger after knowledge,” says Browning. “Have you heard,” wrote Gui Patin to a friend a hundred years after the death of the famous revolutionary, “that ‘Paracelsus’ is being printed at Geneva in four volumes in folio? What a shame that so wicked a book should find presses and printers which cannot be found for better things. I would rather see the Koran printed. It would not deceive so many people. Chemistry is the false money of our profession.” HIS PHARMACY. The composition of Paracelsus’s laudanum, the name of which he no doubt invented, has never been satisfactorily ascertained. Paracelsus himself made a great secret of it, and probably used the term for several medicines. It was generally, at least, a preparation of opium, sometimes opium itself. He is believed to have carried opium in the pommel of his sword, and this he called the “stone of immortality.” Next to opium he believed in mercury, and was largely influential in popularising this metal and its preparations for the treatment of syphilis. It was principally employed externally before his time. He mocked at “the wooden doctors with their guaiacum decoctions,” and at the “waggon grease with which they smeared their patients.” He used turpith mineral (the yellow sulphate), and alembroth salt (ammonio-chloride), though he did not invent these names, and it is possible that he did not mean by them the same substances as the alchemists did. Operinus states that he always gave precipitated mercury (red precipitate, apparently) as a purgative. He gave it in pills with a little theriaca or cherry juice. This he also appears to have designated laudanum. It is certain that he gave other purgatives besides.