The inventions of radio, movies, television and computers have all caused seers to predict the death of books, yet the bound tomes are still with us and thriving in their original print form. However, there’s a few books we could do without … and that’s not a call for a real Fahrenheit 451. Librarians in Denmark attempting to translate three medieval books discovered instead that a strange green coating on them had enough poison to kill an average reader. Does this remind anyone of a novel or movie?
“We tried to identify the Latin texts used, or at least read some of their content. But then we found that the Latin texts in the covers of the three volumes were hard to read because of an extensive layer of green paint which obscures the old handwritten letters. So we took them to the lab.”
That’s when Jakob Holck, a research librarian at the University of Southern Denmark took the mysterious 16th and 17th century green books to Kaare Lund Rasmussen, an Associate Professor in Physics, Chemistry and Pharmacy at the university. Fortunately, both were wearing gloves when they handled the manuscripts. According to their report in The Conversation, Rasmussen tried an X-ray technique using micro-XRF (Micro X-ray fluorescence spectrometry) to filter out the green in order to read the writing underneath it. Instead, he found something else.
“But what the analysis revealed is that the layer of green pigments was arsenic. This substance is among the most toxic in the world and can be exposed to it can lead to various forms of poisoning, the development of cancer, even death.”
Rasmussen had discovered that the pages, covers and bindings were coated with Paris Green, known chemically as copper (II) triarsenite acetate or copper (II) acetoarsenite (Cu(C2H3O2)2·3Cu(AsO2)2). If you’re no longer up on your Periodic Table of Elements, that ‘As’ near the end is the symbol for arsenic, which is toxic to humans and other creatures when it’s touched or inhaled. While this sounds like something a mad monk bent on murder might do to books (did you guess The Name of the Rose by Umberto Eco?), Holck says in this case it was used as a pesticide and insecticide to protect the books from rodents and insects. Paris green is in fact a very effective, albeit dangerous, pesticide and insecticide – farmers using it on apple crops noticed it also burned the trees and the ground underneath them. It was heavily sprayed during World War II over parts of Italy to kill mosquitoes and used in Paris sewers to kill rats (hence the name).
Before you pat yourself on the back for collecting old paintings instead of old books, Paris green pigment was used in the early nineteenth century by impressionist and post-impressionist painters because of its versatility, durability and emerald green hue. That’s right – those arsenic-laden paintings can cause irritated stomach, irritated intestines, nausea, diarrhea, skin problems, irritation of the lungs and other nasty conditions up to and including death. And Holck and Rasmussen point out that it wasn’t just used in paintings.
“The dark Victorian stories of children killed in their room by the emanations of the green wallpaper are not legends.”
If you’re looking to withdraw one of these poison books for nefarious purposes, Holck says they’re now kept in separate cardboard boxes with security tags in a ventilated cabinet. Anyone interested in them will get more that a “Shhh!” from this heavily gloved and masked librarian.