value as such.38
Stoffwechsel in this sense takes place as changes of different commodities through their exchanges, and Formwechsel between money and commodity occurs at the same time. Stoffwechsel proceeds within the sphere of circulation, when necessary use values are distributed among private producers similar to the way blood provides each organ with necessary nutrients. In this usage Marx usually adds the adjective “social”: “Insofar as the process of exchange transfers commodities from hands in which they are non-use-values to hands in which they are use-values, it is a process of social metabolism.… We therefore have to consider the whole process in its formal aspect, that is to say, the change in form or the metamorphosis of commodities through which the social metabolism is mediated.”39 This juxtaposition of Formwechsel and Stoffwechsel in Capital also indicates Marx’s original methodological approach to treat the objects of his investigation from both “material” (stofflich) and “formal” (formell) aspects.
Marx’s usage of Stoffwechsel and Formwechsel differentiates from that of Wilhelm Roscher, who employed the same set of categories before Marx’s Grundrisse. This comparison is particularly interesting because Marx read volume 1 of Roscher’s Principles of Political Economy, published in 1854, before writing the Grundrisse and wrote down a number of vertical lines to highlight relevant paragraphs in his personal copy.40 Roscher also integrated new discoveries of physiology and opposed his own “historical and physiological method” of national economy to the “idealist” one, so that Marx encountered various physiological analogies while he read the book.41 Furthermore, Roscher openly refers to the physiological analogy of “metabolism” in a national economy:
The greater portion of the national capital is in a state of constant transformation. It is being continually destroyed and reproduced. But from the standpoint of private economy, as well as from that of the whole nation, we say that capital is preserved, increased or diminished accordingly as its value is preserved, increased or diminished.
In a footnote to the last sentence, Roscher continues to argue: “J. B. Say, Traité d’Economie Politique I, ch. 10. Only think of the famous principle of metabolism (Stoffwechsel) in physiology!”42 Unfortunately, the relevant pages in Marx’s personal copy are missing, so we cannot tell how he reacted to this passage.
Referring to Say’s Traité, Roscher also deals with the Formwechsel of capital in the production process, in which capital is consumed and transformed into another shape without interruption. With Formwechsel, Roscher means change of material shapes, rather than changes of economic forms between money and commodity, as Marx does. Say writes in one of the relevant passages in chapter 10 of the Traité: “In manufacture, as well as agriculture, there are some branches of capital that last for years; buildings and fixtures for instance, machinery and some kinds of tools; others, on the contrary, lose their form entirely; the oil and potash used by soap-makers cease to be oil and pot-ash when they assume the form of soap.”43 Roscher calls these constant transformations of various materials in the everlasting process of production and consumption within a society Stoffwechsel, similar to Liebig’s comprehension of the physiological process of an organ that sustains its equilibrium in spite of the constant changes of production, consumption, assimilation, and excretion. This analogy nonetheless marks Roscher’s theoretical limitation, for, though he contrasts “form” and “material,” he is not able to abstract the pure economic exchanges of form between commodity and money, but instead confuses the role of exchanges of form with the transformation of matter. Despite this decisive difference between Marx and Roscher, Roscher’s argument clearly shows that Marx’s contemporary economists were also willing to use the physiological concept for their own analysis of the modern economy.
The connection between the Stoffwechsel of physiology and political economy was often mentioned at the time. Even Liebig himself referred to an analogy between organisms and the state economy in his Familiar Letters on Chemistry:
As in the body of an individual, so also in the sum of all individuals, which constitutes the state, there goes on a change of matter [Stoffwechsel], which is a consumption of all the conditions of individuals and social life. Silver and gold have to perform in the organism of the state the same function as the blood corpuscles in the human organism. As these round discs, without themselves taking an immediate share in the nutritive process, are the medium, the essential condition of the change of matter, of the production of the heat and of the force by which the temperature of the body is kept up, and the motions of the blood and all the juices are determined, so has gold become the medium of all activity in the life of the state.44
Liebig’s analogy, based on an organic theory of the state, is crude, absent an analysis of money within the capitalist society. It is still interesting that the proponent of the concept of metabolism tried to connect physiology and political economy, a project soon taken up by Roscher and Marx.
Also, the agriculturalist in Munich, Carl Fraas, whom Marx intensively studied in 1868, emphasized the importance of “metabolism” for political economy: “Organism and metabolism—therefore, metabolism in the national economy, too! It builds the natural scientific foundation of national economy that was almost completely neglected until now in order to develop mere mathematical economics. However, such national economy only investigates and combines data without grasping their cause!”45 Even if there is no direct proof that Marx read Liebig’s Familiar Letters on Chemistry or Fraas’s article, it is conceivable, given the scientific discourse then, that Marx was also led to adopt this new physiological concept in his system of political economy.46
In the Grundrisse, there is one more usage of metabolism, the “metabolism of nature,” which proceeds independently of human intervention. Use values “are dissolved by the simple metabolism of nature if they are not actually used.”47 This “natural metabolism (natürlicher Stoffwechsel),” as chemical dissolution or modification of material substances, for example, occurs through oxidation and decomposition. Marx refers to this phenomenon again in Capital: “A machine which is not active in the labor process is useless. In addition, it falls prey to the destructive power of natural metabolism.”48 Labor alone cannot create natural substances; it can only modify their shapes according to various purposes. Labor provides the “natural substance” with “external form.”49
For example, the form of a desk that labor provides to the “natural substance” of wood is “external” to the original substance because it does not follow the “immanent law of reproduction.” Although the immanent law maintains the wood in its specific form of a tree, the new form of a desk cannot reproduce its substances in the same way, so that it now starts to get exposed to the natural force of decomposition. In order to protect the product of labor from the power of natural metabolism, a purposeful regulation of metabolism through productive consumption is required, which nonetheless cannot overcome the force of nature. Marx on the one hand emphasizes the human ability of labor to consciously and purposefully modify nature, but on the other hand he recognizes the inevitable limitations and restrictions imposed by nature on the human ability to control the metabolism of nature. He is aware of a certain tension between the immanent law of nature and the external form of nature artificially created by labor. The negligence of this material necessity results in decay and destruction of products by natural laws and natural forces.
To sum up, Marx in the Grundrisse employed the concept of metabolism of political economy with three different meanings and continues to do so until Capital: “metabolic interaction between humans and nature,” “metabolism of society,” and “metabolism of nature.” His sources of inspiration are not so apparent after his reading of Roland Daniels and Wilhelm Roscher because, following his own purpose of developing a system of political economy, Marx generalized and modified the concept as well. Precisely because of this generalization, Marx’s
