The base of this acid, or the acid itself, abounds in the mineral, vegetable, and animal kingdoms. In the mineral kingdom it is found in combination with lead in the green lead ore; with iron in the bog-ores, which afford cold-short iron; and more especially with calcareous earth in several kinds of stone. Whole mountains in the province of Estramadura, in Spain, are composed of this combination of phosphoric acid and lime. In the animal kingdom it is found in almost every part of the bodies of animals which are not considerably volatile: there is not, in all probability, any part of these organized beings which is free from it. It has been obtained from blood, flesh, both of land and water animals; from cheese; and it exists in large quantities in bones, combined in calcareous earth. Urine contains it not only in a disengaged state, but also combined with ammonia.