According to Marx, then, capital manifested itself as gold at the beginning of the sixteenth century. It is just as if anybody were to say that specie had expressed itself as cattle for three thousand years, because formerly cattle had performed the gold functions along with others. Only Herr Duehring could be guilty of such a crude and distorted expression. Marx in his analysis of the economic forms in which the process of the circulation of commodities takes places simply declares gold to be the last form. "This last product of the circulation of commodities is the form in which capital first appears. Historically capital comes with the possession of property in the form of money, as hoards of money, merchant-capital, and usury-capital.... This history is going on every day before our eyes. New capital comes on the scene, that is the market,--the market for commodities, the labor market or the money market, simply as money, money which is transformed into capital by a definite process." Again Marx states the fact. It is useless for you to struggle against it, Herr Duehring, Capital must express itself in gold. Marx further examines the process by which money is transformed into capital and discovers that the form in which money circulates as capital is the inversion of the form in which it circulates as the universal equivalent. The individual owner of commodities sells to buy, he sells what he does not need, and buys with the money thus obtained what he does need. The budding capitalist buys on the contrary what he does not want himself, he buys to sell, and to sell for a higher money value than he put into the business, he makes a money profit, and this profit Marx calls surplus value. What is the origin of this surplus value? Either the buyer buys goods below their value or the seller sells them above their value. In both cases gain and loss would balance one another, since every buyer is also a seller. It can also not arise from extortion, for extortion might enrich one at the expense of the other but it could not increase the total sum of money neither could it increase the amount of commodities in circulation. "The entire capitalist class of a country cannot overreach itself." Now, we find that the totality of the capitalist class in every country grows richer before our very eyes, by the process of selling dearer than it bought, by appropriating surplus value. So we are just at the beginning of the discussion. Where does this surplus value come from? This question has to be answered on purely economic grounds to the exclusion of all cheating, and all invasion of force. How is it possible to keep selling dearer than one buys under the assumption that equal values are always exchanged for equal values?