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Secrets of Alchemists’ 600-Year-Old Textbook Hidden in Strange Stains and Grime

The half-magic, half-science practice of Alchemy is still shrouded in mystery. Far from merely an obsessive quest to transmute lead in gold, alchemy was an old and complex school of study that laid much of the foundation for the modern fields of chemistry and medicine. In 2014, the Science History Institute (then called the Chemical Heritage Foundation) acquired an extensive collection of alchemical tomes from a private collector, including a 600-year-old leather-bound book titled (in quintessential medieval wizard style) Recipes and Extracts on Alchemy, Medicine, Metal-Working, Cosmetics, Veterinary Science, Agriculture, Wine-Making, and Other Subjects, or “the Harry Potter book” as it’s referred to at the SHI.

It’s an alchemy textbook, with gold nails driven into the cover in the shape of a six pointed star. Written in Latin by an Italian alchemist between 1425 and 1450 C.E.,  it includes helpful instruction on how to make a dying horse appear well-fed, healthy, and beautiful; flea extermination, the removal of evil beasts from your home, and how to conjure a basilisk. The basilisk conjuring used to be in there, at least. The table of contents lists it, but those pages were removed at some point. Curious.

It also contains “centuries of grime,” according to the Philadelphia Inquirer — soot marks and burns, blemishes and strange stains of unknown origin — most likely the very ingredients listed in the collection of recipes. That’s one problem with alchemical texts, says the Science History Institute, they weren’t written as documentation for scientists 600 years later, they were subjected to heavy lab-work and filled their purpose as alchemical “cookbooks.” Hence, many are unreadable, and many more were destroyed long ago. It might be that the stains and grime are key to unlocking the alchemists’ secrets, according to researchers at the University of Pennsylvania.

Erin Connelly, Postdoctoral Fellow at the University of Pennsylvania and part of the team researching these mysterious texts, says that researchers are often dissuaded by the condition that Alcemists’ writings are usually in:

“These are manuscripts that have traditionally been pushed aside and dismissed due to their dirty or stained appearances.”


This is a basilisk. If I was a betting man, I’d say the pages were removed for our own safety.

In this case the stains could be anything from blood to heavy metals, and the identification of the substance would offer a valuable look into the actual practices of the alchemists. In the case of the basilisk book, there is one purple blotch on page 68 that has researchers’ attention. To identify it, they use a technique called multi-spectral imaging, which involves extremely bright lights and extremely high resolution cameras to identify a substance based to the wavelengths of the light it reflects. The substance needs to be on record already if it’s to be matched, however, and since the stain is almost certainly Basilisk venom, that may be a little difficult.

Alchemist's laboratory

Artists painting of an alchemist and his laboratory.

Once the stain project is completed, the texts will be released to the public, available for download. Imaging consultant Michael Toth says it’s as much about preserving the works as it is altruism:

“It used to be you locked your books in a library. You didn’t want them stolen. Now, if there’s a virus, or a server goes down, or a file is corrupted, it’s going to be somewhere else.”

So keep an eye out for this research to be finished. The next time you need to con someone into the purchase of a dying horse you might have an alchemical ace-in-the-hole.