We have already seen that Marx does not say that the surplus product of the industrial capitalist, of which he is the first owner, is always exchanged for its value, as Herr Duehring points out. Marx plainly says that trade profit only constitutes a portion of the surplus value and under the foregoing conditions this is only possible if the factory proprietor sells his product under value to the trader and thus parts with a portion of the booty. Marx' contention rationally put is How is surplus value transformed into its subordinate forms, profit, interest, trade-profits, ground rents etc.? and this question Marx undertakes to answer in the third volume of Capital. But since Herr Duehring cannot wait long enough for the second volume to appear he has in the meantime to take a close look at the first volume. He thereupon reads that the immanent laws of capitalistic production, the course of the development of capitalism, realise themselves as the necessary laws of competition and thus are brought to the consciousness of the individual capitalists as dominant motives. That therefore a scientific analysis of competition is only possible when the real nature of capital is grasped, just as the apparent movement of heavenly bodies can only be understood by apprehending their real movement, and not merely those movements which are perceptible to the senses. So Marx shows how a certain law, the law of value, appears under given conditions in the competitive system and makes evident its impelling force. Herr Duehring might have understood that competition plays an important role in the distribution of surplus values, and, after sufficient thought, might have grasped at least the outlines of the transformation of surplus value into its subordinate forms from the examples given in the first volume.