In most English treatises on economics, a price means a sum of money given in exchange for a commodity, or the ratio between the money and the commodity, or the ratio between the value of the money and the value of the commodity. In any case, price as a rule involves the idea of money. With the Germans, on the other hand, _Preis_ means any exchange ratio (or a quantity of commodities of any sort given in exchange for a good), whether or not one of the terms of the ratio involves money, and the distinction between price and value (_Preis_ and _Wert_) is, commonly, the distinction between the measure and the thing measured, or between "relative value" and "absolute value" in Ricardian phrase.[198] The conception of price has been broadened by some later writers in English, however, to correspond with the German usage, notably by Professor Patten,[199] and by Professor Schumpeter,[200] in an English article contributed recently to the _Quarterly Journal_. I do not care to argue a merely terminological question, and I readily concede that there are disadvantages in departing from familiar usage. But, on the other hand, since I am convinced that ratios of exchange in general, and money prices in particular, are generically the same, while ratios of exchange and values are generically as unlike as it is easily possible for two things to be, I shall use the term price in this wider meaning, and confine the word value, in the exposition of my own theory, to the non-relative meaning. The distinction between prices in this sense and absolute values appears in Adam Smith and in Ricardo. These writers do not adhere very strictly to either meaning of the term, value, however.[201] The conception of absolute values is lost by J. S. Mill, and the distinction which he draws in connection with the problem of the standard of deferred payments (not so called by Mill) is between values (relative) and _cost of production_.[202] In Cairnes, the two conceptions are hopelessly confused on a single page,[203] while Marshall's whole treatment runs in terms of price. In what follows, I wish to generalize the conception of price, to show the function of the price concept in economics, to distinguish carefully between the theory of value and the theory of prices, and to see what light the theory of value outlined in this book throws upon the problems of the price analysis.