price, and can really be paid off, even though it be by means of pain to the author. Whence is it that this ancient deep-rooted and now perhaps ineradicable idea has drawn its strength, this idea of an equivalency between injury and pain? I have already revealed its origin, in the contractual relationship between creditor and ower , that is as old as the existence of legal rights at all, and in its turn points back to the primary forms of purchase, sale, barter, and trade.