Study Unwraps Ancient "Recipe" for Mummies
for National Geographic News
|October 30, 2001|
Researchers studying Egyptian embalming practices have opened a window on the techniques and materials used in the ancient mummification process.
The Egyptians mummified their dead because they believed that a person needed his body in the afterlifeand the better-looking the better, so it was incumbent on the priests in charge of embalming to do a good job.
"We were interested in what you would have to know to mummify someone and keep them intact for thousands of years," said Richard Evershed.
Evershed and Stephen Buckley, organic chemists at the University of Bristol in the United Kingdom, studied 13 mummies dating from across a 2,300-year period, from roughly 1985 B.C. to A.D. 395.
They conclude that Egyptian embalmers had an incredibly sophisticated understanding of the natural materials they used.
"Mummification is all about inhibiting microbial growth and dehydration," said Evershed. "The Egyptians figured out that it's not enough to just take the guts out, cover the body with inorganic salt, and then pop the body in a tomb in that state.
"The tombs could be very humid and the body would rehydrate" without proper preparation, he said. "They knew that if the body was not treated, what they'd get would be a pile of dust."
Sarah Wisseman, director of ancient technologies at the University of Illinois, Urbana-Champaign, agrees. "The study shows that Egyptian embalmers were experts, extremely familiar with the anti-bacterial properties of the materials, and may have something to teach us about preservation," she said.
The study, and a companion piece by Wisseman, were published in the October 25 issue of the journal Nature.
The Egyptians began mummifying their dead around 2600 B.C. Over the centuries, the practice evolved to include extremely elaborate rituals conducted by priests using chemically complex recipes for preserving the body.
Mummification practices peaked from around 1570 to 1075 B.C. Tutankhamun and other famous mummies are from this period.
At the height of the art, embalming methods were so sophisticated that scientists today have been able to occasionally recover DNA samples from hair and tissues, said Wisseman.
By the Greco-Roman era of Egyptian history, 332 B.C. to A.D. 395, preservation of the body was not as important. More focus was given to making the mummified person more attractive through the use of paints and face masks, said Wisseman.
Knowledge of embalming practices can help in dating mummies, but it also gives archaeologists information about ancient trade routes, the rise and influence of embalming guilds, the availability of local versus exotic materials, and changing burial techniques.
Looking to Eternity
The embalming process in Egypt took 70 days and was performed by priests, who formed guilds. The embalming tents were located away from the city center because the smell of decaying human bodies was horrible, despite the use of fragrant herbs and spices.
Because the Egyptians had figured out that decay begins within the body, they removed many of the internal organs before covering the body with natron, a native Egyptian salt, said Evershed.
The natron, which was also put in packets and stuffed into the body cavities, dehydrated the body. When the body was completely dehydrated, it was wrapped.
The linen wrappings were treated with resins from fir and pine trees, beeswax, myrrh, palm wine, cassia, camphor oil, and other substances that had drying or anti-bacterial properties.
"The embalmers really had to have a tremendous amount of knowledge about the properties of these materials and their ability to prevent rehydration and inhibit microbial growth to truly protect the bodies over a long period of time," said Evershed.
The researchers analyzed embalming material by using a combination of gas chromatography and mass spectrometry to examine extremely small samples"less than 0.1 milligrams, and in some cases as little as one or two fibers," said Evershed. The analysis revealed that the main products used to treat all the mummies were derived from plant, and to a lesser extent animal, oils.
"Buckley and Evershed found more substances, such as plant and animal oils, used in the mummification process than had been documented in earlier studies," said Wisseman.
"The presence of these oils," she added, "suggests that Egyptians may have used less expensive materials as a base, and then added the more exoticand expensiveembalming agents, which makes complete sense to me."
More Studies Expected
This was the first systematic study of organic materials of mummies with known dates and origins, said Evershed. "Earlier studies have looked at one or two mummies at a time," he said, "but that has no meaning archaeologicallyyou need a number of samples in chronological order."
The technique the researchers used should prove a boon to mummy studies, said Wisseman.
Previously, scientists wanting to analyze the mummification process faced an obstacle because their need for specimens entailed damage to valuable museum pieces.
"This research opens other avenues for study," said Wisseman, who was formerly a museum curator. "And because this technique uses such tiny samples, museum curators are likely to be more willing to contribute specimens for study."
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