Calomel was introduced into practice by Sir Theodore Turquet de Mayerne about the year 1608. It has been said that he was the inventor of the product, but as it was described and, perhaps, to some extent used by other medical authorities, Crollius among these, who lived and died before Turquet was born, this was evidently impossible. Theodore Turquet de Mayerne had been a favourite physician to Henri IV, but he had been compelled to leave Paris on account of the jealousies of his medical contemporaries. His employment of mineral medicines, antimony and mercury especially, was the occasion of bitter attacks, but his professional heresy was perhaps actually less heinous than his firm Protestantism. Both James I and Charles I accepted his services and placed great confidence in his skill. He was instrumental, as explained in another section, in the independent incorporation of the apothecaries, and was also one of the most active promoters of the publication of the “London Pharmacopœia.” It appears likely that Turquet invented the name by which this milder form of mercurial has come to be most usually known. The alchemical writers of the time called it Aquila Alba or Draco Mitigatus. A notorious Paracelsian of Paris, Joseph Duchesne, but better known by his Latinised surname of Quercetanus, who shared with Turquet the animosity of Gui Patin and his medical confederates, and for similar reasons, also made calomel and administered it, probably sold it, under the designation of the mineral Panchymagogon, purger of all humours. Panacea mercurialis, manna metallorum, and sublimatum dulce, were among the other fanciful names given. It was believed by the old medical chemists that the more frequently it was resublimed the more dulcified it became. In fact, resublimation was likely to decompose it, and thus to produce corrosive sublimate.