Adipocere also known as corpse, grave or mortuary wax, is a wax-like organic substance formed by the anaerobic

Anaerobic organism

An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It could possibly react negatively and may even die if oxygen is present...

 bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

l hydrolysis

Hydrolysis

Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...

 of fat

Fat

Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...

 in tissue, such as body fat in corpses. In its formation, putrefaction

Putrefaction

Putrefaction is one of seven stages in the decomposition of the body of a dead animal. It can be viewed, in broad terms, as the decomposition of proteins, in a process that results in the eventual breakdown of cohesion between tissues and the liquefaction of most organs.-Description:In terms of...

 is replaced by a permanent firm cast of fatty tissues, internal organs and the face.

History

Adipocere was first described by Sir Thomas Browne in his discourse Hydriotaphia, Urn Burial

Hydriotaphia, Urn Burial

Hydriotaphia, Urn Burial, or a Discourse of the Sepulchral Urns lately found in Norfolk, is a work by Sir Thomas Browne, published in 1658 as the first part of a two-part work that concludes with The Garden of Cyrus....

(1658):

The chemical process of adipocere formation, saponification

Saponification

Saponification is a process that produces soap, usually from fats and lye. In technical terms, saponification involves base hydrolysis of triglycerides, which are esters of fatty acids, to form the sodium salt of a carboxylate. In addition to soap, such traditional saponification processes...

, came to be understood in the 17th century when microscope

Microscope

A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...

s became widely available.

Augustus Granville

Augustus Granville

Augustus Bozzi Granville MD, FRS was a physician, writer, and Italian patriot.Born in Milan, he studied medicine before leaving to avoid being enlisted in Napoleon's army. After practicing medicine in Greece, Turkey, Spain, and Portugal, he joined the British Navy and sailed to the West Indies...

 is believed to have somewhat unwittingly made candles from the adipocere of a mummy

Mummy

A mummy is a body, human or animal, whose skin and organs have been preserved by either intentional or incidental exposure to chemicals, extreme coldness , very low humidity, or lack of air when bodies are submerged in bogs, so that the recovered body will not decay further if kept in cool and dry...

 and used them to light the public lecture he gave to report on the mummy's dissection.

Appearance

Adipocere is a crumbly, waxy, water-insoluble material consisting mostly of saturated fatty acid

Fatty acid

In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...

s. Depending on whether it was formed from white

White adipose tissue

White adipose tissue or white fat is one of the two types of adipose tissue found in mammals. The other kind of adipose tissue is brown adipose tissue....

 or brown

Brown adipose tissue

Brown adipose tissue or brown fat is one of two types of fat or adipose tissue found in mammals....

 body fat, adipocere is grayish white or tan in color.

In corpses, the firm cast of adipocere allows some estimation of body shape and facial features, and injuries are often well-preserved.

Formation

The transformation of fats into adipocere occurs best in the absence of oxygen in a cold and humid environment, such as in wet ground or mud at the bottom of a lake or a sealed casket, and it can occur with both embalmed and untreated bodies. Adipocere formation begins within a month of death, and in the absence of air it can persist for centuries. An exposed, infested body or a body in a warm environment is unlikely to form deposits of adipocere.

Corpses of women, infants and overweight persons are particularly prone to adipocere transformation because they contain more body fat. In forensic science, the utility of adipocere formation to estimate the postmortem interval is limited because the speed of the process is temperature-dependent. It is accelerated by warmth, but temperature extremes impede it.