There are two ways in which the quantity of money may be included in a general equilibrium system: as a datum, whose value is fixed exogenously, or as an unknown, whose value is determined by the equilibrium system itself. Let them be called active money and passive money, respectively. Current monetary theory uses the first approach. The Ricardo-WalrasKeynes tradition in general equilibrium models is clearly of the activemoney variety. This is also true of the more contemporary versions, such as Patinkin's well-known system (1965).' Apart from the main stream of thought, however, a number of analyses exist which imply passive money. The gold-standard model, as it is usually expounded, belongs to this class. The price of gold in terms of money is given, while the stock of money is endogenously determined by the set of equilibrium conditions. The form in which the quantity of money adapts to its equilibrium level differs according to the institutional mechanism: Convergence is assured through monetization and demonetization of gold in the pure goldcurrency system, and through convertibility of notes into gold and vice versa in the gold-standard system with paper money. In either case, the money supply is allowed to conform to its equilibrium volume. This kind of monetary system, in which the money price of a certain product or commodity is a datum and the quantity of money a dependent magnitude, may be denoted in general as a commodity standard.