This Latin word for liver referred to reddish-brown ( i.e., liver-colored) metal sulfides. (See sulphuret.) Hepar sulphuris ( liver of sulphur) was a synonym either for potassa sulphurata (a mixture of various compounds of potassium and sulfur made by fusing potassium carbonate and sulfur) [ Cavendish, Priestley, Stahl] or, in homeopathic contexts, for calcium sulfide, CaS.