For a long time capital was known only under the form of merchants' capital and usurers' capital; for it was only, or almost only, under those two forms that money bred its like, and it is this possibility of money's breeding which constitutes capital. This possibility could not exist, except as an exceptional fact, for money invested in the means of production, so long as industry remained more or less domestic in character. In order for capital to spread beyond the domain of commerce in goods and money and appear in the domain of production, it was necessary for the wealth accumulated in commerce and usury to effect on a large scale the concentration of the scattered petty producers and their petty individual tools; the workshop had to be enlarged; it was necessary to bring together a large number of workers working at the same time, in the same place, under the orders of the same "captain of industry," in producing on a large scale the same kind of commodity, and to find for the disposal of the latter a sufficiently extended market. The money advanced in production can, in fact, realize an appreciable profit by the sale of the objects produced, only when its possessor is able to realize a certain quantity of surplus-labor; now, to accomplish this he must have a certain number of laborers. For it is the surplus-labor realized, we know, that forms the excess of the value produced over that of the money laid out in production, or, in other words, the surplus-value which incessantly swells the capital and continually increases its power to dominate labor. The capitalist mode of production, the mode of production in which the means of labor function as capital, owes to capital its specific character, which is its power of making money breed money, of giving birth to surplus-value. The capitalist purchaser of labor-power has only one object, viz., to enrich himself by making his money breed or expand, by the process of making commodities containing more labor than he pays for, and by selling which he therefore realizes a value greater than that of the sum of the advances or outlays made.