Horse Glue

I was reading an article this morning that reminded me of a conversation I had with my sister and sister-in-law on Chanukah. I said something about glue being made from horses... and my sister-in-law thought it was a myth.

So, this morning, I finally got around to looking it up, and here's the source for horses going to the glue factory.

From Straight Dope: I don't know much about the site, but from what they say, and who they source, they seem to be credible.

"It's mostly used as a figure of speech these days, but yes, horses typically were sent to the glue factory or rendering plant back in the days when they were mostly used as work animals. These days, it's more common (an undocumented source says 90% of all domestic horses) for unwanted horses to be sent to a slaughterhouse if still alive, or a rendering plant (AKA the knackers, the knackery) if deceased.

Animal (origin) glue is made from connective tissue, found in hoofs, bones, tendons, ligaments, and cartilage in vertebrate animals.

Rendering plants are the recycling links in the food chain. They take fat and bone trimmings from grocery stores, waste scraps from restaurants, and dead animals. They cook the meat and fat products together and grind it up. It's used for animal feed and non-edible products like soap, various lubricants, and of course glue--the heavy kind that's used to glue furniture together, for example. "

Other fun facts I came across here:
(a site completely devoted to telling you what kind of glue to use for what!!)

When you are sucking in all the toxins from your cigarette, you can rest assured that the glue used to hold it together is completely non-toxic. It is made from a combination of casein (milk) and wax (to increase moisture resistance), and is absolutely harmless.

The Aztec Indians in Central America used animal blood mixed with cement as a mortar for their buildings, many of which still remain standing today.