Profit (profit of enterprise plus interest) and rent are nothing but peculiar forms assumed by particular parts of the surplus-value of commodities. The magnitude of surplus-value is the limit of the total size of the parts into which it may be divided. Average profit plus rent are, therefore, equal to the surplus-value. It is possible for part of the surplus-labour, and thus surplus-value, contained in the commodities, not to take part directly in the equalisation of an average profit, so that part of the commodity-value is not expressed at all in its price. But first, this is balanced either by the fact that the rate of profit increases, when the commodities sold below their value form an element of the constant capital, or by profit and rent being represented by a larger product, when commodities sold below their value enter into the portion of value consumed as revenue in the form of articles for individual consumption. Secondly, this is eliminated in the average movement. At any rate, even if a portion of surplus-value not expressed in the price of the commodity is lost for the price formation, the sum of average profit plus rent in its normal form can never be larger than the total surplus-value, although it may be smaller. Its normal form presupposes wages corresponding to the value of labour-power. Even monopoly rent, in so far as it is not a deduction from wages, i.e., does not constitute a special category, must always indirectly be a part of the surplus-value. If it is not part of the price excess above the price of production of the commodity itself, of which it is a constituent part (as in differential rent), or an excess portion of the surplus-value of the commodity itself, of which it is a constituent part, above that portion of its own surplus-value measured by the average profit (as in absolute rent), it is at least part of the surplus-value of other commodities, i.e., of commodities which are exchanged for this commodity having a monopoly price. The sum of average profit plus ground-rent can never be greater than the magnitude of which they are components and which exists before this division. It is therefore immaterial for our discussion whether the entire surplus-value of the commodities, i.e., all the surplus-labour contained in the commodities, is realised in their price or not. The surplus-labour is not entirely realised if only for the reason that due to a continual change in the amount of labour socially necessary to produce a certain commodity, resulting from the constant change in the productiveness of labour, some commodities are always produced under abnormal conditions and must, therefore, be sold below their individual value. At any rate, profit plus rent equal the total realised surplus-value (surplus-labour), and for purposes of this discussion the realised surplus-value may be equated to all surplus-value; for profit and rent are realised surplus-value, or, generally speaking, the surplus-value which passes into the prices of commodities, thus in practice all the surplus-value forming a constituent part of this price.