Why did the Egyptians use natron for artificial embalming? An experimental study on organ mummification

The high standard of artificial mummification in ancient Egypt seems to result from a long period of empiric assessment. However, it still remains unclear why the ancient Egyptians used specific dehydration substances, such as natron, and not other comparable ones, such as sea salt (widely used for conserving foodstuffs). In order to contrast the effect of natron and salt in artificial mummification, we compared two pig hearts of similar size. One was embedded in natron, the other in sea salt up to 69 days at 37°C using Egyptian mummification procedures. The total weight of the two samples differed significantly during the period of observation, but was most obvious during the first 5 weeks. The heart in natron dehydrated more rapidly than the heart in salt. Histological tissue preservation was better in the natron sample. We suggest that empiric observations led the ancient Egyptians to realize the functional advantages of natron over sea salt, leading to optimal conservation of cadavers.