The theoretical conception concerning the first transformation of surplus-value into profit, that every part of a capital yields a uniform profit, expresses a practical fact. Whatever the composition of an industrial capital, whether it sets in motion one quarter of congealed labour and three-quarters of living labour, or three-quarters of congealed labour and one-quarter of living labour, whether in one case it absorbs three times as much surplus-labour, or produces three times as much surplus-value than in another — in either case it yields the same profit, given the same degree of labour exploitation and leaving aside individual differences, which, incidentally, disappear because we are dealing in both cases with the average composition of the entire sphere of production. The individual capitalist (or all the capitalists in each individual sphere of production), whose outlook is limited, rightly believes that his profit is not derived solely from the labour employed by him, or in his line of production. This is quite true, as far as his average profit is concerned. To what extent this profit is due to the aggregate exploitation of labour on the part of the total social capital, i. e., by all his capitalist colleagues — this interrelation is a complete mystery to the individual capitalist; all the more so, since no bourgeois theorists, the political economists, have so far revealed it. A saving of labour — not only labour necessary to produce a certain product, but also the number of employed labourers — and the employment of more congealed labour (constant capital), appear to be very sound operations from the economic standpoint and do not seem to exert the least influence on the general rate of profit and the average profit. How could living labour be the sole source of profit, in view of the fact that a reduction in the quantity of labour required for production appears not to exert any influence on profit? Moreover, it even seems in certain circumstances to be the nearest source of an increase of profits, at least for the individual capitalist.