ghendel:

These neat life-like mummies were made by Italian Giovanni Battista Rini in the early 1800s.  Until now, nobody knew how he did it and they were mostly forgotten. Scientists ran them through a CT scan and chemically analyzed the tissues, and found that Rini “petrified” the body parts by bathing them in a cocktail of mercury and other heavy metals. The study on the heads is set to be released next week in the journal Clinical Anatomy. It’s like a 19th century Body World exhibit!

See more here.