Fixed rates of exchange require in the long run international equilibrium, and the question arises, how the equilibrium can be maintained under a policy which pursues national as well as international ends. If the price the countries belonging to the common standard had to pay for their international membership was that of a practically inflexible domestic policy, the membership would be too highly paid for. The introduction of a difference between the Banks' buying and selling prices for the combination will be an important step in lessening the rigidity with which the common international standard links the member countries together. A margin between the buying and selling price, however, would extend the difference between the "metal points" and so enable the Banks, to a greater extent than before, to pursue their own interest policy without the loss of monetary metals.