Mummy-makers used elaborate recipes
The process of embalming in Ancient Egypt was more sophisticated than previously thought, new analysis shows.
Richard Evershead and Stephen Buckley of the University of Bristol completed a chemical analysis of 13 mummies. They found that embalmers used a wider variety of ingredients, and changed their techniques more frequently, than other research has shown.
The work is notable because detailed information was extracted from very small amounts of tissue, leaving the mummies almost completely untouched.
The results appear in Nature this week.
The mummies were all of a known age, spanning 2300 years. The researchers concentrated on mummies from the Pharaonic (or dynastic) period, which is regarded as the time of 'classic' mummy-making culture.
They used a combination of gas chromatography and mass spectrometry, techniques chosen for their ability to analyse small samples.
"The amount of sample required is an important consideration," state the authors.
The sample size of less than 0.1 mg, they say, "facilitates the virtual non-destructive analysis of valuable museum specimens".
The researchers found that embalming fluids contained resins from conifers and the pistachio tree, as well as coniferous pitch and beeswax the amounts of which increased in later mummies, possibly because of their antibacterial properties.
It seems the Egyptians were able to stretch out their expensive materials.
"The presence of plant oils (and to a lesser extent animal fats) suggests that they were key ingredients in mummification," write the researchers.
"They were probably used as a less-costly base with which to mix and apply more exotic embalming agents to the bodies and/or wrappings."
The embalming materials and procedures vary more than expected, both within single dynasties and between historical periods, comments Sarah Wisseman from the University of Illinois in the News and Views section of the same issue of Nature.
"This could be a result of economics (the cost and availability of materials), changing fashions, and/or the preferences of particular embalming guilds," she writes.
"Wealthy Egyptians may have deliberately chosen the more expensive embalming fluid to impress family and friends, just as well-to-do people today select exotic woods and metal trims for their relatives' coffins."
Our understanding of the substances used in embalming has been incomplete to date. The written account of Herodotus refers to myrrh, cassia, palm wine, 'cedar oil' and 'gum', but was written around 450BC, well after the peak of the mummification process (1,3501,000BC).
Previous chemical analyses confirmed the use of a natural salt called natron, juniper oil, camphor oil, myrrh, coniferous and other resins, but the authors claim that these earlier studies suffered from the lack of modern analytical techniques.
The authors warn that we still have much to learn about mummification, however. They point out that the term embalming 'wax' is as valid as 'resin' given the amount of beeswax used in embalming.
"It is especially interesting to note that the Coptic word for wax is 'mum'," they point out.
The Egyptian culture embalmed dead bodies to allow the spirit Ka to reenter the body so it could go into the afterlife. To facilitate this, the body had to protected from decay, so they removed organs that cause decay and treated the body with preservatives.
Salts, resins, cedar oil, palm wine, myrrh, cassia, gum, honey and bitumen all worked by drying the body out or fighting microbes.