A book from the British Library reveals how Santorio Santorio, who lived between 1561 and 1636, came up with an explanation for how matter works two decades before Galileo Galilei.

Santorio’s marginal note to col. 406C-D, in Santorio Santori, Commentaria In Primam Fen Primi Libri Canonis Avicennae (Venice, 1625), British Library, 542.h.11. Courtesy of the British Library.

You might think your library is big, but it’s just peanuts to the British Library. The second largest library in the world holds over 150 million cataloged books, from all times and from all fields. Naturally within this gargantuan collection, also lie books which have not yet been properly explored. This was the case with 1625 edition of a book called Commentaria in primam Fen primi libri Canonis Avicennae (A Commentary on the First Fen of the First Book of Avicenna’s Canon), until it was discovered by Dr. Fabrizio Bigotti, from the Centre for Medical History at the University of Exeter.

Bigotti analyzed the handwriting and writing style and concluded that the book was almost certainly written by Santorio Santorio. Inside the book, Santorio (who is also credited with inventing the thermometer and other early medical devices) came up with a good explanation of how matter works. He did not share the elemental vision of nature, as most people presumably did at the time. To make it even better, he did this twenty years before Galileo, who is largely credited with this breakthrough.

“The notes show he did not see the world not made up of four elemental qualities – hot, cold, dry and moist – as Aristotle had suggested. This helped to start the process of getting rid of the idea that magic and the occult could be found in nature,” Bigotti explains.

The idea that the world is made from invisible ‘corpuscles’ is not really new. It was actually devised by the Greek philosopher Democritus, which is a stunning achievement in itself. But until Galileo Santorio, no one was able to prove that. He carried out a series of optical experiments, as well as urine distillation experiments, all of which indicated that all matter was made of tiny particles.

This discovery makes the case for a deeper study of early modern chemistry in the Medical School of Padua, where Santorio taught, and the work carried out there between the end of the sixteenth and the beginning of the seventeenth century. Santorio’s true contribution to chemistry has been forgotten but, I hope, this new discovery means that will no longer be the case.

It’s always thrilling to see just how far people could get with what we today would consider rudimentary instruments. The discovery further establishes Santorio as one of the most brilliant scientists in history.

“It was already known that Santorio laid the foundations for what is understood today as evidence-based medicine and the study of metabolism,” Dr. Bigotti said. “The new discovery shows he was he among the first scientists to suggest the body aims at preserving its own balance through discharge of invisible particles.”