Adipocere or grave wax or mortuary wax is the insoluble fatty acids left as residue from pre-existing fats from decomposing material such as a human cadaver. It is formed by the slow hydrolysis of fats in wet ground and can occur in both embalmed and untreated bodies. It is generally believed to have first been discovered by the Frenchman Fourcroy in the 18th century; however, Sir Thomas Browne describes this substance in his discourse, Hydriotaphia, Urn Burial of 1658: "In a Hydropicall body ten years buried in a Church-yard, we met with a fat concretion, where the nitre of the Earth, and the salt and lixivious liquor of the body, had coagulated large lumps of fat, into the consistence of the hardest castle-soap: wherof part remaineth with us." In essence, in this process the usual dissolution of putrefaction is replaced by a permanent firm cast of fatty tissues. This allows