Gold coin has produced its substitutes, first metallic and then paper, only because in spite of its loss of metallic weight it continued to perform the function of coin. It did not circulate because of its wear and tear; on the contrary, it wore out to a symbol because it continued to circulate. Only in so far as gold money becomes simply a token of its own value in the process of circulation, can mere tokens of value take its place. In so far as the movement C―M―C represents a dynamic unity of two processes C―M and M―C which pass directly one into the other, or in so far as a commodity passes through the complete process of its metamorphosis, it express its exchange value in price and in money only to discard that form at once and to become again a commodity or, rather, a use-value. That is to say, it develops _only an apparent assertion of the independence_ of its exchange value. On the other hand, we have seen that gold, in so far as it performs the function of coin or in so far as it continually circulates, actually forms only a connecting link between the metamorphoses of commodities and constitutes _but their transitory money form_; furthermore, that it realizes the price of one set of commodities only in order to realize that of another, but in no case does it constitute a stable form of exchange value or appear itself as a commodity in a state of rest. The reality which the exchange value of commodities acquires in the process and which is represented by gold in its circulation, is the reality of an electric spark. Although real gold, it plays the part of fictitious gold, and can, therefore, be replaced in this function by a token of itself.