o demand causes an oscillation of prices, but it is not the
determinant of value. When prices rise above a certain level, demand
slackens or ceases, and prices are inevitably lowered. Prices may and do
fall with a decreased demand, but it is clear that unless the producers
can get a price approximately equal to the value of their commodities,
they will cease to produce them, and the supply will diminish or cease
altogether. Ultimately, therefore, the fluctuations of price through the
lack of equilibrium between supply and demand adjust themselves, and
prices must tend constantly to approximate values.

Monopoly-price is, as already observed, an artificial price in the sense
that the laws of free market exchange do not apply to it. The "unique
utilities," things not reproducible by human labor, command what might
be termed natural monopoly-prices. There are many other commodities,
however, the price of which is not regulated by the quantity of social
human labor necessary to produce them, but simply by the desire of the
purchasers and the means they have of gratifying it and the power of the
sellers to control the market and exclude effective competition. Since
Karl Marx wrote, the exceptions to his law of value have become more
numerous, as a result of the changes in industrial and commercial
conditions. The development of great monopolies and near-monopolies has
greatly increased the number of commodities which, for considerable
periods, are placed outside the sphere of the labor-value theory, their
price depending upon their marginal utility, irrespective of the labor
actually embodied in them or necessary to their reproduction. It may, in
the opinion of the present writer, be said in criticism of the followers
of Marx that they have not carried on his work, but largely contented
themselves with repeating generalizations which, true when made, no
longer fit all the facts. But that is not a criticism of Marx, or of his
work. What he professed to make was an analysis of the methods of
production and exchange in competitive capitalist society. His followers
have largely failed to allow for the enormous changes which have taken
place, and go on repeating, unchanged, his phrases.

Professor Seligman has pointed out that Ricardo's contention that value
is determined by the cost of production, and the contention of Jevons
that value is determined by marginal utility, are not mutually
exclusive, but, on the contrary, compleme