Essentially, the capitalist process of production is simultaneously a
 process of accumulation. We have shown that with the development of capitalist
 production the mass of values to be simply reproduced, or maintained, increases
 as the productivity of labour grows, even if the labour-power employed should
 remain constant. But with the development of social productivity of labour the
 mass of produced use-values, of which the means of production form a part,
 grows still more. And the additional labour, through whose appropriation this
 additional wealth can be reconverted into capital, does not depend on the
 value, but on the mass of these means of production (including means of
 subsistence), because in the production process the labourers have nothing to
 do with the value, but with the use-value, of the means of production.
 Accumulation itself, however, and the concentration of capital that goes with
 it, is a material means of increasing productiveness. Now, this growth of the
 means of production includes the growth of the working population, the creation
 of a working population, which corresponds to the surplus-capital, or even
 exceeds its general requirements, thus leading to an over-population of
 workers. A momentary excess of surplus-capital over the working population it
 has commandeered, would have a two-fold effect. It could, on the one hand, by
 raising wages, mitigate the adverse conditions which decimate the offspring of
 the labourers and would make marriages easier among them, so as gradually to
 increase the population. On the other hand, by applying methods which yield
 relative surplus-value (introduction and improvement of machinery) it would
 produce a far more rapid, artificial, relative over-population, which in its
 turn, would be a breeding-ground for a really swift propagation of the
 population, since under capitalist production misery produces population. It
 therefore follows of itself from the nature of the capitalist process of
 accumulation, which is but one facet of the capitalist production process, that
 the increased mass of means of production that is to be converted into capital
 always finds a correspondingly increased, even excessive, exploitable worker
 population. As the process of production and accumulation advances therefore,
 the mass of available and appropriated surplus-labour, and hence the absolute
 mass of profit appropriated by the social capital, must grow. Along
 with the volume, however, the same laws of production and accumulation increase
 also the value of the constant capital in a mounting progression more rapidly
 than that of the variable part of capital, invested as it is in living labour.
 Hence, the same laws produce for the social capital a growing absolute mass of
 profit, and a falling rate of profit.