Or it may be that the surplus of the one party is not sufficient for the needs of the other, and that the latter will refrain from giving all that he possesses; he will keep some part of it in order to obtain from a third party the additional quantity indispensable to his need; this deducted portion which the second party will try to reduce to a minimum, since he needs all the first's surplus gives rise to price: it is no longer an excess of wheat that is being exchanged for an excess of wine, but, as the result of an altercation, so many hogsheads of wine for so many bushels of wheat.