The fact that the capital laid out in wages belongs in the circulating part of productive capital and, unlike the fixed component of productive capital, shares the quality of fluency with a part of the objective product creators, the raw materials, etc., has nothing whatever to do with the role played in the process of self-expansion by this variable part, as distinct from the constant part of capital. This refers only to how this part of the advanced capital-value is to be replaced, renewed, hence reproduced out of the value of the product of means of the circulation. The purchase and repurchase of labour-power belong in the process of circulation. But it is only within the process of production that the value laid out in labour-power is converted (not for the labourer but for the capitalist) from a definite, constant magnitude into a variable one, and only thus the advanced value is converted altogether into capital-value, into capital, into self-expanding value. But by classing, like Smith, the value expended for the means of subsistence of the labourers, instead of value laid out in labour-power, as the circulating component of productive capital, the understanding of the distinction between variable and constant capital, and thus the understanding of the capitalist process of production in general, is rendered impossible. The determination that this part of capital is variable capital in contrast to the constant capital, spent for material creators of the product, is buried beneath the determination that the part of the capital invested in labour-power belongs, as far as the turnover is concerned, in the circulating part of productive capital. And the burial is brought to completion by enumerating the labourer’s means of subsistence instead of his labour-power as an element of productive capital. It is immaterial whether the value of the labour-power is advance in money or directly in means of subsistence. However under capitalist production the latter can be but an exception.[24]