About Robert Boyle and the Theory of Therapeutic Precious Stones

I am not altogether of their mind, that absolutely reject the internal use of Leaf-Gold, Rubies, Saphyrs, Emeralds, and other Gems, as things that are unconquerable by the heat of the stomach. For as there are rich Patients that may, without much inconvenience, goe to the price of the dearest Medicines; so I think the Stomach acts not on Medicines barely upon the account of its heat, but is endowed with a subtle dissolvent (whence never it hath it) by which it may perform divers things not to be done by so languid a heat. And I have, with Liquors of differing sorts, easily drawn from Vegetable Substances, and perhaps unrectified, sometimes dissolved, and sometimes drawn Tinctures from Gems, and that in the cold... But that which I chiefly consider on this occasion is, that 'tis one thing to make it probable, that is, possible, Gold, Rubies, Saphyrs, etc., may be wrought upon by humane Stomach; and another thing to shew both that they are wont to be so, and that they are actually endowed with those particular and specifick Virtues that are ascribed to them; nay and (over and above) that these Virtues are such and so eminent, that they considerably surpass those of cheaper Simples. And I think, that in Prescriptions made for the poorer sort of Patients, a Physician may well substitute cheaper Ingredients in the place of these precious ones, whose Virtues are no half so unquestionable as their Dearnesse.