My favorite Twenties poison! I use Rough on Rats in SILENT MURDERS (due out in September), but not to kill anyone. No . . . another poison kills my victims. Still, I have a special place in my heart for Rough on Rats ever since I found some of the advertisements for the product. Aren’t they great? I bought them on eBay, and I bring them to book club meetings whenever I’m invited to visit.
I’ve been reading the POISONER’S HANDBOOK by Deborah Blum and was delighted to see her discuss Rough on Rats. I learned a good deal about the stuff: it was a grayish powder made of 10 % soot and 90 % arsenic. Arsenic was a much-used ingredient in dyes to color wallpaper, fabric, boxes, greeting cards, candles, toys, paints, Venetian blinds, carpets soap, and jewelry. In other words, it was everywhere. Even wallpaper untainted by arsenic (it made a lovely green) could be poisonous because paperhangers mixed arsenic in their paste in the belief that it would keep rats from gnawing into the walls.
The author makes the point that it was hard to pin arsenic murder on a particular person because anyone could buy arsenic easily (in drugstores, grocery stores, or garden supply stores) and virtually everyone had it at home, whether they knew it or not, because it was an ingredient in medicines and creams prescribed by doctors as well as used for weed killers, bug killers, and rat killers. So arsenic was a foolproof way to kill someone–until the advent of forensic science in the Twenties.