As a rule, the capitalist cannot sell under cost price without becoming bankrupt, but he can quite easily sell under the production price, and mostly does so. In the example already given, his rate of profit amounts to over 28 per cent. According to the degree of competition, or by reason of other circumstances which we will examine in the next chapter, he can content himself with a rate of profit of 10, 15, or 20 per cent., which will serve him partly as an income and partly be expended in the development of his enterprise. The 28 per cent. profit generally forms a circle within which he fixes his manufactured price. Under favourable circumstances he can add the whole 28 per cent, to the price; under less favourable, only 20, 15, or 10 per cent. Accordingly, several portions of surplus value remain in the commodities which are not yet realised. What happens to them? The remaining portions of profit or of surplus value fall to the large or small traders who are interposed between producer and consumer, or go in the form of interest to the banking institutions, in the event of the capitalist operating with borrowed money. As the profit is only realised in the process of circulation (in commerce and exchange) and there divided amongst the various economic classes and sections, most people believe that profit arises in commercial transactions. They do not know that the price of a commodity can only be increased in trade because its manufactured price was fixed below its price of production or its value, that is, because the commodities contain surplus value which is only gradually realised in the process of circulation. The social significance of this doctrine is far-reaching. If it is correct, then all the social sections which are not engaged as manual and brain workers in the process of production, or in the transport of raw material, lead a parasitical life and consume the surplus value which is squeezed by the capitalist class out of the proletariat and appropriated without payment. Quite otherwise are capitalist ideas. According to them, profit is the result both of the spirit of the enterprise and the ability of the capitalist, added to that portion of the capital which is put into the process of production: the machines and buildings and raw materials which are used up, and the labour power, all of which are bought at their proper exchange value. It is only fit and proper that the trader and moneylender should receive a portion of the profit so created, for they assist in realising the exchange value by bringing the commodities to the consumer, and thus rendering possible the process of production. Surplus value or profit? Labour or Capital? Behind this question lurks the great class struggle of the modern social order. No wonder the Marxian doctrine of value and surplus value was the occasion for an extensive controversy, in which the famous problem of the average rate of profit played a great part. 6. _The Average Rate of Profit._