The eruption of Mount Vesuvius in the year AD 79 brought destruction to the historic cities of Pompeii and Herculaneum. Among the thousands of victims was a man whose brain cells were found intact by Italian researchers.
In the 1960s, the remains of the man were discovered in Herculaneum. In 2018, forensic anthropologist Pier Petrone and his team found the "widespread preservation of atypical red and black mineral residues encrusting the bones, which also impregnate the ash filling the intracranial cavity and the ash-bed encasing the skeletons."
The skeletons contained a "glassy material shining" inside, which were brain remnants. Within the iron and iron oxide from residues were the rare preservation of body fluids and soft tissues of victims who were exposed to the extreme heat of the volcanic eruption.
Human Tissue Turned to Glass
Two years later, the team confirmed that the remnants had preserved the brain of a male victim through a process called vitrification, or the transformation of a substance into a glass due to extreme heat then rapid cooling. The findings were published in the New England Journal of Medicine.
Petrone explained that as the brain was exposed to the extreme temperature from the eruption, it was first liquified. Rapid cooling of the volcanic ash soon after immediately turned the man's brain into a glassy material.
A microscopic analysis of the remnant revealed intact brain cells. Petrone described the cells as "incredibly well-preserved with a resolution" found nowhere else. Moreover, there were vitrified remains of intact nerve cells in the man's spinal cord, proteins from the brain, and fatty acids from in human hair, according to the authors.
Traces of carbon and oxygen indicated that the remains contained organic material, most likely the skeleton's brain. Discovered in Herculaneum's Collegium Augustalium, the ancient skeleton is believed to belong to a man who was the building's caretaker, which may have been the headquarters of Emperor Augustus's cult.
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Understanding Vitrification
Cerebral tissues from human remains are rarely preserved, shared with the authors since tissue becomes saponified over time. Saponification is the process where triglycerides react with sodium or potassium hydroxide and produce soap or glycerol and fatty acid salt.
From the samples, the team estimated that the maximum temperature for the process to occur was at 968 degrees Fahrenheit. Volcanologist Guido Giordano explained that charred wood found near the skeleton helped verify the temperature after the eruption nearly 2,000 years ago.
Discovering how the human tissue was perfectly preserved, said Giordano, "opens up the room for studies of these ancient people that have never been possible." For example, victims from more recent events such as firestorms can be analyzed in a similar manner.
Multidisciplinary researchers in various fields, including archaeology, neurogenetics, and biology, continue to study the remains and learn more about the process of vitrification. Expanding their research would include a protein and genetic analysis, said Petrone. The evaluation can also be useful for future volcanic eruptions around the world.
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