5. As there is a twofold value, and a twofold exchange, so a twofold character is impressed on the great instrument of exchange, money. Money, in one character, is an instrument of private exchange: in its other character, to mercantile men more familiar, it is an instrument of commercial exchange. In the one, it represents use value to the particular owner, more or less to him than it would be to some other owner: in the other, it represents market value, the same to all at the same time. 6. Leo X. in the Fifth Council of Lateran, 1515, ruled that--"usury is properly interpreted to be the attempt to draw profit and increment, without labour, without cost, and without risk, out of the use of a thing that does not fructify." In 1745 Benedict XIV. wrote in the same sense to the Bishops of Italy: "That kind of sin which is called usury, and which has its proper seat and place in the contract of _mutuum_, consists in turning that contract, which of its own nature requires the amount returned exactly to balance the amount received, into a ground for demanding a return in excess of the amount received." _Mutuum_, be it observed, is a loan for a definite period, of some article, the use of which lies in its consumption, as matches, fuel, food, and, in one respect, money. We shall prove this to be properly a _gratuitous_ contract. (s. iv., n. 4, p. 254.) 7. Usury then is no mere taking of exorbitant interest. There is no question of more or less, but it is usury to take any interest at all upon the loan of a piece of property, which (a) is of no use except to be used up, spent, consumed: (b) is not wanted for the lender's own consumption within the period of the loan: (c) is lent upon security that obviates risk: (d) is so lent that the lender foregoes no occasion of lawful gain by lending it. 8. When all these four conditions are fulfilled, and yet interest is exacted upon a loan, such interest is usurious and unjust. And why? Simply by reason of the principle that we laid down before, speaking of private exchange (n. 3), a principle that is thus stated by St. Thomas: "If one party is much benefited by the commodity which he receives of the other, while the other, the seller, is not a loser by going without the article, no extra price must be put on. The reason is, because the benefit that accrues to one party is not from the seller, but from the condition of the buyer. Now no one ought to sell to another that which is not his, though he may sell the loss that he suffers. He, however, who is much benefited by the commodity he receives of another, may spontaneously bestow some extra recompense on the seller: that is the part of one who has the feelings of a gentleman." (2a. 2æ, q. 77, art. 1, in corp.)