In this hypothetical illustration, we have the extreme case of what the Commodity or Metallist School seems to assert. In this case, barring temporary emergencies too acute to admit of increasing the money-supply by the method described, their theory that the value of money comes wholly from the commodity value of the standard, would offer a complete explanation. I offer this illustration as the antithesis of the dodo-bone illustration of Nicholson. That illustration sets forth the extreme claims of the quantity theory, and purports to be a case in which the quantity theory would work perfectly. The case illustrative of the commodity theory clearly brings out the fact that that theory rests on exclusive attention to the standard of value function of money. The dodo-bone theory gives exclusive attention to, but very imperfect analysis of, the medium of exchange function. But I submit that the extreme case of the commodity theory, in the illustration I have given, is a thinkable and consistent system. It would work--even though not conveniently. Indeed, it resembles in essentials the plan actually proposed by Aneurin Williams, and later by Professor Irving Fisher[129] for stabilizing the value of money. Substitute a composite commodity for gold, and gold for silver, in the illustration, and you have the essentials of that plan. The dodo-bone hypothesis, however, as I have been at elaborate pains to show in the foregoing, is unthinkable. It would not work. It is, thus, possible to construct a system for which the commodity theory would offer a complete explanation. It is not possible to do this for the quantity theory. But the limiting case for the commodity theory is not the actual case. Standard money is also commonly a medium of exchange. Standard money is particularly desirable in bank and government reserves. Its employment in these and other ways is a valuable employment, and adds directly to its value both as money and in the arts. There is a marginal equilibrium between its values in the two employments. The notion that the only way in which the money employment adds to the value of money is an indirect one, by withdrawing gold from the arts, so lessening its supply and raising its value there, may be proved erroneous by this consideration: what, in that case, would determine the margin between the two employments? What force would there be to withdraw gold from the arts at all? Why should more rather than less be withdrawn? There must be ascending curves on both sides of the margin. Gold money in small amount has a high significance per unit in the money employment. A greater amount has a smaller significance per unit. The marginal amount of gold put to work as money has a comparatively low significance in that employment--a significance just great enough to secure it from the competing employments in the arts. * * * * *