Adipocere

Adipocere or grave 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. It is generally believed to be first discovered by the Frenchmanman 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."

Sources

• J.S.Finch- 'A Doctor's life of Science and Faith' Princeton 1950
• C.A.Patrides ed. Sir Thomas Browne The Major Works. Penguin 1977