But just because the circuit C' ... C' presupposes within its sphere the existence of other industrial capital in the form of C (equal to L + MP) -- and MP comprises diverse other capitals, in our case for instance machinery, coal, oil, etc. -- it clamours to be considered not only as the general form of the circuit, i.e., not only as a social form in which every single industrial capital (except when first invested) can be studied, hence not merely as a form of movement common to all individual industrial capitals, but simultaneously also as a form of movement of the sum of the individual capitals, consequently of the aggregate capital of the capitalist class, a movement in which that of each individual industrial capital appears as only a partial movement which intermingles with the other movements and is necessitated by them. For instance if we regard the aggregate of commodities annually produced in a certain country and analyse the movement by which a part of it replaces the productive capital in all individual businesses, while another part enters into the individual consumption of the various classes, then we consider C' ... C' as a form of movement of social capital as well as of the surplus-value, or surplus-product, generated by it. The fact that the social capital is equal to the sum of the individual capitals (including the joint-stock capital or the state capital, so far as governments employ productive wage-labour in mines, railways, etc., perform the function of industrial capitalists), and that the aggregate movement of social capital is equal to the algebraic sum of the movements of the individual capitals, does not in any way preclude the possibility that this movement as the movement of a single individual capital, may present other phenomena than the same movement does when considered from the point of view of a part of the aggregate movement of social capital, hence in its interconnections with the movements of its other parts, and that the movement simultaneously solves problems the solution of which must be assumed when studying the circuit of a separate, individual capital instead of being the result of such study.
C' ... C' is the sole circuit in which the originally advanced capital-value consists only a part of the extreme that opens the movement and in which the movement from its inception thus reveals itself as the total movement of the industrial capital -- as the movement of that part of the product which replaces the productive capital as well as of that part which forms surplus-product and which on the average is spent in part as revenue and employed in part as an element of accumulation. Included in this circuit is the expenditure of surplus-value as revenue and to that extent individual consumption is likewise included. The latter is furthermore included for the reason that the starting-point C, commodity, exists in the form of some utility; but every article produced by capitalist methods is commodity-capital, no matter whether its use-form destines it for productive or for individual consumption, or for both. M ... M' indicates only the value side, the self-expansion of the advanced capital-value, as the purpose of the entire process; P ... P (P') indicates the process of production of capital as a process of reproduction with a productive capital of the same or of increasing magnitude (accumulation). Revealing itself already in its initial extreme as a form of capitalist commodity production, C'
... C' comprises productive and individual consumption from the start;productive consumption and the self-expansion of value therein included appear only as a branch of its movement.
Finally, since C' may exist in a use-form which cannot enter any more into any process of production, it is indicated at the outset that C''s various constituents of value expressed by parts of the product must occupy a different position, according to whether C' ... C' is regarded as the form of the movement of the total social capital or as the independent movement of an individual industrial capital. All these peculiarities of the circuit lead us beyond its own confines as an isolated circuit of some merely individual capital.
In the formula C' ... C', the movement of the commodity-capital, that is to say, of the total product created capitalistically, appears not only as the premise of the independent circuit of the individual capital but also as required by it. If the formula and its peculiarities are grasped, it is no longer sufficient to confine oneself to indicating that the metamorphoses C'---M' and M---C are on the one hand functionally defined sections in the metamorphoses of capital, on the other are links in the general circulation of commodities. It becomes necessary to elucidate the intertwining of the metamorphoses of one individual capital with those of other individual capitals and with that part of the total product which is intended for individual consumption. On analysing the circuit of an individual industrial capital, we therefore base our studies mainly on the first two forms.
The circuit C' ... C' appears as a form of a single individual capital, for instance in agriculture, where calculations are made from crop to crop. In Formula II, the sowing is the starting-point, in Formula III the harvest, or, to speak with the physiocrats, Formula II starts out with the avance , and Formula III with the reprises f. The movement of capital-value appears in III from the outset only as a part of the movement of the general mass of products, while in I and II the movement of C' constitutes only a phase of the movement of some isolated capital.
In Formula III commodities in the market are the continuous premise of the process of production and reproduction. Hence, if attention is fixed exclusively on this formula all elements of the process of production seem to originate in commodity circulation and to consist only of commodities.
This one-sided conception overlooks those elements of the process of production which are independent of the commodity-elements.
Since in C' ... C' the starting-point is the total product (total value), it turns out that (if foreign trade is disregarded) reproduction on an extended scale, productivity remaining otherwise constant, can take place only when the part of the surplus-product to be capitalised already contains the material elements of the additional productive capital; that therefore, so far as the production of one year serves as the premise of the following year's production or so far as this can take place simultaneously with the process of simple reproduction within one year, surplus--product is at once produced in a form which enables it to perform the functions of additional capital. Increased productivity can increase only the substance of capital but not its value; but therewith it creates additional material for the self-expansion of that value.
C' ... C' is the groundwork for Quesnay's Tableau économique , and it shows great and true discretion on his part that in contrast to M ... M' (the isolatedly and rigidly retained form of the mercantile system)he selected this form and not P ... P.