[...] As simple reproduction constantly reproduces the capital-relation itself, i.e., the relation of capitalists on the one hand, and wage-workers on the other, so reproduction on a progressive scale, i.e., accumulation, reproduces the capital-relation on a progressive scale, more capitalists or larger capitalists at this pole, more wage-workers at that. The reproduction of a mass of labour power, which must incessantly reincorporate itself with capital for that capital’s self-expansion; which cannot get free from capital, and whose enslavement to capital is only concealed by the variety of individual capitalists to whom it sells itself, this reproduction of labour power forms, in fact, an essential of the reproduction of capital itself. Accumulation of capital is, therefore, increase of the proletariat.