I have heard they are from animal intestines and other things and what kind of animals are they from if so? (yourkefirsource.com)
Another head - scratcher for Beyond Meat's scientists was how to replicate a sausage's casing, which is usually made of animal intestine. (fortune.com)
In addition to delighting the bibliophile, the exhibition boasts some scarification knives belonging to Jenner, and a pair of Goa Stones, imitations of stones found in animal intestines believed to ward off the effects of poison. (newscientist.com)