When it comes to sausage, I wouldn't recommend asking too many questions
.... you might ruin a good thing.
Natural casings are pretty much intestines (you asked
). That's the way they used to make sausage before somebody invented man-made casings.1. NATURAL CASINGS
Sausages have historically been manufactured in natural casings. Natural casings are almost exclusively prepared from different parts of the alimentary canal of pigs and ruminants. Pig casings are derived from the stomachs, small intestines (pig casings, smalls or rounds), large intestines (caps and middles) and terminal straight end of the large intestines (bungs).2. ARTIFICIAL CASINGS
Artificial casings offer a uniform cylindrical shape and the choice of any specific diameter and suitable tensile strength as well as resistance to damage. They are filled uniformly and, after filling, sausages can be linked by machine or by hand into required lengths. The artificial casings are made from cellulose, collagen, plastic and other materials.