Spirits of Hartshorn is an aqueous solution of ammonia. Originally this term was applied to a solution manufactured from the hooves and horns of the red deer, as well as those of some other animals. The aqueous solution was a colorless and pungent, consisting of about 28.5 percent ammonia. It was used chiefly as a detergent, for removing stains and extracting certain vegetable coloring agents, and in the manufacture of ammonium salts. Later the term was applied to the partially purified similar products of the action of heat on nitrogenous animal matter generally, and finally the term was applied to any aqueous solution of ammonia.