We have just seen that in the production process the action of living labour preserves the labour-time objectified in the commodities that serve as materials and instruments in the new use-value form of the commodity product; reproduces the cost of its own reproduction; and produces a new value, surplus labour-time.

The use of the living labour that functions in production costs the capitalist only the cost of its reproduction. Therefore, “the capitalist, by means of the exchange process with the worker […] obtains two things free of charge, first the surplus labour which increases the value of his capital; but at the same time, secondly, the quality of living labour which maintains the previous labour materialized in the component parts of capital and thus preserves the previously existing value of capital.”

More (pdf, 79 KB): The Chapter on Capital: Part 14: The Transformation of Surplus Labour into Profit (I): The Accumulation of the Surplus (pp. 365-373)