Marx's magnum opus, ``Capital,'' added bulk and substance to the theses of the Communist Manifesto. It contributed the theory of surplus value, which professed to explain the actual mechanism of capitalist exploitation. This doctrine is very complicated and is scarcely tenable as a contribution to pure theory. It is rather to be viewed as a translation into abstract terms of the hatred with which Marx regarded the system that coins wealth out of human lives, and it is in this spirit, rather than in that of disinterested analysis, that it has been read by its admirers. A critical examination of the theory of surplus value would require much difficult and abstract discussion of pure economic theory without having much bearing upon the practical truth or falsehood of Socialism; it has therefore seemed impossible within the limits of the present volume. To my mind the best parts of the book are those which deal with economic facts, of which Marx's knowledge was encyclopaedic. It was by these facts that he hoped to instil into his disciples that firm and undying hatred that should make them soldiers to the death in the class war. The facts which he accumulates are such as are practically unknown to the vast majority of those who live comfortable lives. They are very terrible facts, and the economic system which generates them must be acknowledged to be a very terrible system. A few examples of his choice of facts will serve to explain the bitterness of many Socialists:-- Mr. Broughton Charlton, county magistrate, declared, as chairman of a meeting held at the Assembly Rooms, Nottingham, on the 14th January, 1860, ``that there was an amount of privation and suffering among that portion of the population connected with the lace trade, unknown in other parts of the kingdom, indeed, in the civilized world. . . . Children of nine or ten years are dragged from their squalid beds at two, three, or four o clock in the morning and compelled to work for a bare subsistence until ten, eleven, or twelve at night, their limbs wearing away, their frames dwindling, their faces whitening, and their humanity absolutely sinking into a stone-like torpor, utterly horrible to contemplate.''[4] [4] Vol. i, p. 227.