The purchase of labour-power for a fixed period is the prelude
 to the process of production; and this prelude is constantly repeated when
 the stipulated term comes to an end, when a definite period of production,
 such as a week or a month, has elapsed. But the labourer is not paid until
 after he has expended his labour-power, and realised in commodities not
 only its value, but surplus-value. He has, therefore, produced not only
 surplus-value, which we for the present regard as a fund to meet the private
 consumption of the capitalist, but he has also produced, before it flows
 back to him in the shape of wages, the fund out of which he himself is
 paid, the variable capital; and his employment lasts only so long as he
 continues to reproduce this fund. Hence, that formula of the economists,
 referred to in Chapter XVIII, which represents wages as a share in the
 product itself. [2] What flows back to the labourer in the shape of wages is a portion of the product that is continuously reproduced
 by him. The capitalist, it is true, pays him in money, but this money is
 merely the transmuted form of the product of his labour. While he is converting
 a portion of the means of production into products, a portion of his former
 product is being turned into money. It is his labour of last week, or of
 last year, that pays for his labour-power this week or this year. The illusion
 begotten by the intervention 533of money vanishes immediately,
 if, instead of taking a single capitalist and a single labourer, we take
 the class of capitalists and the class of labourers as a whole. The capitalist
 class is constantly giving to the labouring class order-notes, in the form
 of money, on a portion of the commodities produced by the latter and appropriated
 by the former. The labourers give these order-notes back just as constantly
 to the capitalist class, and in this way get their share of their own product.
 The transaction is veiled by the commodity form of the product and the
 money form of the commodity.