Starkey's move to London was followed by remarkable success in establishing a medical practice and producing and administering medicinal remedies to patients, including Robert Boyle. However, despite his success, Starkey abandoned his patients in 1651 to pursue the "secrets" of alchemy, which included the production of pharmaceuticals and the transmutation of metallic substances. For example, Starkey's "sophic mercury" was an amalgam of antimony, silver, and mercury, which was supposed to dissolve gold into a mixture that when heated, would produce the mythical philosopher's stone, an agent for transmuting base metals into noble ones. It is also known that Starkey tutored Boyle in the practice of chemistry and experimentation, although Boyle never acknowledged Starkey's tutelage.