Ge Hong was the most famous alchemist of China. He strongly believed in the ability to transform anything and everything, given the proper procedure; that especially included transforming man from a mortal to an immortal being. He was a careful observer of nature; in relation to medicine he provided detailed descriptions of serious diseases (such as smallpox and tuberculosis) and described formulas for treating serious medical situations in his Handbook of Prescriptions for Emergencies. Sun Ssu-mo was one of his admirers.