Again, humans are implicated in the promotion and distribution of our own misery. However, if bitumen was wrongly credited with darkening the skin of mummified remains, what caused it?

Robert Fizek
Newton, Mass.

The coating on the mummies was actually a rub made up of oils, spices, salts, and tree resins. These substances, particularly the resins, dried and darkened as they aged .—S. Perkins