With Stephens's recipe in hand, Hartley set to work with Stephen Hales, along with two colleagues in France, to locate the medicine's chemically active ingredients. These were slaked lime (calcium hydroxide) and Alicant soap (predominantly potassium oleate, like other soaps an alkaline salt of a fatty acid). Hales had shown that some bladder stones rapidly dissolved in boiled soap-lye (caustic potash, potassium hydroxide). What was needed, then, was a safely ingestible preparation that would turn a person's urine alkaline; and this, they concluded, is what the slaked lime and soap combination did. In 1739 Hales won the Copley Medal for his work, and the following year Hartley published their results in a Latin volume, De Lithontriptico, in Basel and Leiden, the latter being home at the time to the foremost medical school in Europe.
With Stephens's recipe in hand Hartley set to work with Stephen Hales, along with two colleagues in France to locate the medicine's chemically active ingredients. These were slaked lime (calcium hydroxide) and Alicant soap (predominantly potassium oleate, like other soaps an alkaline salt of a fatty acid). Hales had shown that some bladder stones rapidly dissolved in boiled soap-lye (caustic potash, potassium hydroxide) What was needed, then, was a safely ingestible preparation that would turn a person's urine alkaline; and this, they concluded, is what the slaked lime and soap combination did. In 1739 Hales won the Copley Medal for his work, and the following year Hartley published their results in a Latin volume, De Lithontriptico, in Basel and Leiden, the latter being home at the time to the foremost medical school in Europe.