Why an American doctor wrote the most poisonous book ever

"Shall we poison our homes?" 

That's the incipit of Shadows from the Walls of Death, by American physician Robert Kedzie. 

Published in 1874 in Michigan, the 100-page volume would become a record-breaking affair. However, it was originally compiled to warn Kedzie's contemporaries about a silent, mysterious threat that endangered the population and killed in plain sight. 

Soon enough, Shadows from the Walls of Death would be known as the most poisonous book ever.

Mind you, Shadows from the Walls of Death is not a book about poison: it's a collection of poison-infused, mass-produced paper. 

Calling out the very real dangers of arsenic-based green dyes, the author's scrupulous research collected samples of toxic wallpaper that each contained between one and four grams of arsenic. 

"Perhaps we could not devise a more effectual way to contaminate the air in our homes with a small amount of arsenical dust, than by the use of wall paper coloured with arsenical preparations," writes Kedzie in the introduction.

The popularity of wallpaper skyrocketed after 1840, when the first mass-production wallpaper printing machines began to appear. 

As production increased exponentially "prices dropped to as little as a farthing a yard (0.25p)."

That also meant that entire houses were covered in colourful patterns - delicate white, blue, red and green designs became fashionable, thus generating a true health emergency as children began to fall ill and die under mysterious circumstances. 

The book contains 86 leaves of wallpaper (all commercially available at the time) that the author identified as dangerous: in total, that amounts to 36 grams of arsenic.

A room covered in wallpaper presenting arsenic-based dye (often mixed with other shades) could have contained up to 167 grams of arsenic. 

Such quantity was more than enough to harm an adult’s health – even worse, a bedroom sporting even the most delicate hint of green could damage irreparably the chances of survival of a patient who had been prescribed bed rest.

"A delicate shade of pea-green satisfies the eye much more than a white wall," Kedzie writes.

"But in toned paper the arsenical green is often so disguised by combination with other colours as to escape notice, and the danger is increased by the fact that the whole surface of paper is spread with the poison."

Arsenic-based greens were significantly widespread during the Victorian era: other than wallpaper, they were used on clothes and curtains, and newspaper offices were inundated with toxic fumes due to the ink imbued with arsenic. 

Breathing arsenic-filled fine dusts at home every day turned houses into giant, silent killing machines.

Arsenic green was so highly venomous that a popular shade called Paris green (also used in foods to give them a pleasant, verdant shade) was converted to insecticide in the 1930s, becoming one of the first examples of chemical pesticides in the world. 

Manipulating it would often lead to factory poisoning accidents. 

In the book's introduction, the author cites the case of a woman who had been "an invalid for some time": strangely, her health always improved when she was away from home. 

However, every time she was forced to rest in her bedroom (with bright green figures printed on the wallpaper), her condition worsened.

Similarly, all the young children of a lawyer from Mason passed away due to a mysterious illness after the house was "prepared with wall paper". Once the green wallpaper was examined, it was found to contain 1.88 grams of arsenic per square meter (equivalent to 1550.0 square inches).

Kedzie also mentions Emma, a nine-year-old child who slept in a stone-green bedroom and suffered from chronic pains, fatigue and fever. As customary she was instructed to rest, which further worsened her condition. 

When the wallpaper of her bedroom was analyzed, it was found to contain 3.4 grams of arsenic per square metre. 

After Emma was promptly removed from the room, her health improved and she fully recovered.

Only four copies of the book's original 100-copy print run survive, and each either has its pages safely sealed in plastic or is stored in an air-tight container. 

As of 2021, the remaining copies are safely stored in university libraries. 

Harvard University Medical School owns a copy of the record-breaking tome, while the others are owned by Michigan State University, the U.S. National Library of Medicine in Maryland and the University of Michigan. 

The digital copy of the book is free to access.

Ever since, several other libraries have discovered ancient harmful books on their shelves, often because of the vibrant greens injected in the covers and spines. 

Nothing, however, comes close to the poisonous Shadows from the Walls of Death.

Did you know about this dangerous book? 

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