Somewhere in the epoch of time, man learned to tan hides to make soft supple clothing, bags, and such. I do not quite fathom how he reasoned that mashing the brains of the animal, and working it into the hide, would work, but it did. The hide was then smoked to color it. This would have been a natural thought as some of the early shelters were bent limbs covered with hides. Most likely they would have had a small fire inside. Without tanning a hide, a green hide will become stiff like cardboard. It can be worked soft and supple by effort, but if it gets wet, it will get stiff. Basically, as I understand this, there is a chemical called collagen in the hide which act like glue. When the fibers are coated, as in braining, the collagen can not set up. A green hide is often refered to as rawhide. Basically, all that might be done to made rawhide is just fleshing the inner hide to remove the meat, fat, and gore so that it will not rot. Some Native Americans used these as rawhide mats inside their tipis as ground coverings. Containers such as parfleche (French for rawhide) envelopes and boxes were made. Fleshing and dehairing hides, I mainly use rawhide for bindings. Wetting dry rawhide makes it easier to cut with an obsidian blade. Pictured is a spear with rawhide wrappings around the hollowed end that receives the foreshaft so that it will not split. Next to it, a stone blade attached to an adze - a chopping implement. The rawhide is soaked in water, stretched, and wrapped on. As it dries it shrinks and becomes stiff making a secure binding. Hide scraps were saved, I had read, and eaten in times of hunger. Perhaps it was one of those times when scraps were put into a pot, and they boiled down to a brown sticky goo - that hide glue was discovered. Basically, the collagen was disolved out of the hide and the water boiled off. The brown object in the upper right is dried hide glue I had made. Unless you dry it, it will spoil. To reconstitute it all you do is grind it to a powder, add water, and heat. Often, bindings are covered with hide glue. The tools pictured are laying on the flesh side of a rawhide mat. It is interesting, nature provides...you just need to learn how to use it.