In 1996 in Switzerland's Lake Brienz, the corpse of a drowned man was found floating in the water. What is peculiar about this particular discovery is that the man was estimated to have died more than 300 years prior. So why didn't his body decay, losing the mystery of his death to time? His remains had been preserved in a natural phenomenon called corpse wax—known more scientifically as adipocere.
Corpse wax is a waxy, organic substance that is formed by the anaerobic bacterial hydrolysis of fat in tissue. When this process takes effect, a dead body is firmly set in a permanent cast of fat tissue, rather than breaking down in death's fifth stage, putrefaction. Depending on what kind of fat tissue the wax is forming from—white or brown–the resulting corpse wax can either be a gray-white or tan color.
But why do some corpses generate wax while others deteriorate? The process of forming corpse wax—saponification—occurs most often in environments high in moisture and low in oxygen. This means a body is more likely to undergo this fascinating change if it is located in wet ground, the mud at the bottom of a lake, or a sealed and damp casket. Any body exposed to air or infected with insects has a very low chance of developing these wax deposits.
Corpse wax occurs in both embalmed and untreated bodies, though it's more likely to be found in those who were women, infants, or overweight, as they stored more body fat. Corpses begin to form wax within a month of their death, and this process can last for centuries so long as the body is denied exposure to oxygen.
Once a body preserved in corpse wax is examined, the saponification process isn't a very useful tool for determining when a person has died. Temperature is a major factor in how quickly a corpse produces wax. Warmth speeds up the wax formation, but an extreme on either end of the thermometer results in significant impediment of deposits. The exhumation of a body and the resulting exposure to air, handling, dissection, and enzymatic activity of microbiota begins the process of breaking down the corpse wax.
Corpse wax was given the formal name adipocere in the late 18th century. In 1786, Paris's Cemetery of Innocents began the yearlong process of digging up graves to move the skeletal remains to the mines which are now known as the infamous Paris Catacombs. The scientists supervising the exhumation, Antoine-François de Fourcroy and Michel-Augustin Thouret, studied the waxy substance and drew from the Latin words "adeps" for fat and "cere" for wax.
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Some find that corpse wax has a soapy texture and appearance, resulting in some preserved corpses being called "soap mummies." As such, one famous case of this phenomenon is the Soap Lady. Her body was discovered in Philadelphia in 1875 when city improvements were underway. It was originally believed that she died in her late 20s around 1792 during the Yellow Fever epidemic, though an X-ray in 1986 revealed buttons not manufactured until the 1830s. When water seeped into her coffin, the saponification process began. Her mummified body now resides in Philadelphia's Mütter Museum.
The Higgins brothers are perhaps the most well-known examples of corpse wax. In Scotland in 1911, the brothers were murdered by their own father. However, as their bodies were left to float in a flooded quarry, their preserved remains were recovered in 1913, with more than enough evidence for police to charge the proper killer. A portion of the brothers' remains were secretly tucked away for research at Edinburgh University, but roughly a century later a relative requested the return of the remains for an appropriate Christian burial.
As you can imagine, such preservation of the dead is an incredible and enlightening discovery for scientists and archaeologists. However, corpse wax can be bad news for graveyards. Some cemeteries recycle grave plots every few decades, moving the bodies out after they've completely decade. But, as was the case for some German graveyards back in 2008, there was so much corpse wax build up that some bodies hadn't experienced any decomposition. This meant that the cemeteries either had to work around the issue with burial chambers or undergo an expensive process of soil reconditioning.
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Corpse wax inspires many different reactions in people, from the baffling to the eerie to the downright inconvenient. But this natural phenomenon is always a fascinating and informative sight to behold.