The Egyptian embalmers knew how to distinguish from the other viscera, the liver, the spleen, and the kidneys, which they did not disturb; they had discovered the means of withdrawing the brain from the interior of the body without destroying the bones of the cranium; they knew the action of alkalies upon animal matter, since the time was strictly limited that the body could remain in contact with these substances; they were not ignorant of the property of balsams, and resins to protect the bodies from the larvae of insects and mites; they were likewise aware of the necessity of enveloping the dried and embalmed bodies, in order to protect them from the humidity, which would interfere with their preservation.
The preceding is a description of ancient Egyptian embalming as given by Herodotus, and has been the subject of numerous commentations, discussions and researches. It is almost a positive fact that Herodotus has omitted desiccation, and that it naturally took place during the time consecrated to preparation. From the mummies examined it is believed now that the body was first salted for seventy days, then dried, and that it was not until after this desiccation that the resinous and balsamic substances were applied. A simple inspection of the mummies is sufficient to confirm this opinion and besides what use would have been these resinous matters, with which the alkali of the natrum would soon form a soapy mass, which the lotions would have carried off, at least in great part? It is much more reasonable to suppose that these balsamic and resinous substances were not applied to the bodies until after they were withdrawn from the natrum.
All the ancients agree, in saying that the Egyptians made use of the various aromatics to embalm the dead; that they employed for the rich myrrh, aloes, canella, and cassia lignea; and for the poor, the cedria, bitumen, and natrum. The natrum was a mixture of carbonate, sulphate, and muriate of soda. It was a fixed alkali, which acted after the manner of quicklime; despoiling the bodies of their lymphatic, and greasy fluids, leaving only the fibrous and solid parts. The odoriferous resins and bitumen not only preserved from destruction, but also kept at a distance the worms and beetles which devour dead bodies.