Thus, the value of the annual commodity-product, just like the value of the commodity-product produced by some particular investment of capital, and like the value of any individual commodity, resolves itself into two component parts: A, which replaces the value of the advanced constant capital, and B, which is represented in the form of revenue — wages, profit and rent. The latter component part of value, B, is counterposed to the former A, in so far as A, under otherwise equal circumstances: 1) never assumes the form of revenue and 2) always flows back in the form of capital, and indeed constant capital. The other component, B, however, carries within itself, in turn, an antithesis. Profit and rent have this in common with wages: all three are forms of revenue. Nevertheless they differ essentially in that profit and rent represent surplus-value, i.e., unpaid labour, whereas wages represent paid labour. The portion of the value of the product which represents wages expended thus replaces wages, and, under the conditions assumed by us, where reproduction takes place on the same scale and under the same conditions, is again reconverted into wages, flows back first as variable capital, as a component of the capital that must be advanced anew for reproduction. This portion has a two-fold function. It exists first in the form of capital and is exchanged as such for labour-power. In the hands of the labourer, it is transformed into revenue which he draws out of the sale of his labour-power, is converted as revenue into means of subsistence and consumed. This double process is revealed through the mediation of money circulation. The variable capital is advanced in money, paid out as wages. This is its first function as capital. It is exchanged for labour-power and transformed into the manifestation of this labour-power, into labour. This is the process as regards the capitalist. Secondly, however: with this money the labourers buy a part of the commodities produced by them, which is measured by this money, and is consumed by them as revenue. If we imagine the circulation of money to be eliminated, then a part of the labourer’s product is in the hands of the capitalist in the form of available capital. He advances this part as capital, gives it to the labourer for new labour-power, while the labourer consumes it as revenue directly or indirectly through exchange for other commodities. That portion of the value of the product, then, which is destined in the course of reproduction to be converted into wages, into revenue for the labourers, first flows back into the hands of the capitalist in the form of capital, or more accurately variable capital. It is an essential requirement that it should flow back in this form in order for labour as wage-labour, the means of production as capital, and the process of production itself as a capitalist process, to be continually reproduced anew.