Unfortunately, further intellectual exchange between Marx and Daniels was interrupted when the latter was arrested in June 1851 in Cologne because of his political activity. He suffered terrible conditions in prison, and after his release died, on August 29, 1855. Marx wrote on September 6, 1855, to his widow, Amalie Daniels:
It is impossible to describe the grief I felt on hearing that dear, unforgettable Roland had passed away.… Seen amongst the others in Cologne, Daniels always seemed to me like the statue of a Greek god deposited by some freak of fate in the midst of a crowd of Hottentots. His premature decease is an irreparable loss not only to his family and friends but also to science, in which he gave promise of the finest achievements, and to the great, suffering mass of humanity, who possessed in him a loyal champion.… It is to be hoped that circumstances will some day permit us to wreak upon those guilty of cutting short his career vengeance of a kind sterner than that of an obituary.35
Even if Marx did not discuss the concept in detail in Reflection, his reading of Mikrokosmos clearly prepared a foundation for the further integration of natural sciences into political economy before his excerpts from Liebig’s Agricultural Chemistry.
Subsequently, Marx’s usage of the term metabolism became more general and systematic during the process of witing the Grundrisse. In the passage from the Grundrisse quoted above, Marx deals with the incessant interaction between humans and nature with this physiological analogy, treating nature as the inorganic body of humanity. In this vein, Marx discusses the labor process as “metabolic interaction with nature,” that is, as material interaction of three moments of production taking place within nature: raw materials, means of production, and human labor. According to Marx, this “production process in general” is “common to all social conditions” as long as humans produce within nature.36 Humans must work and produce, constantly taking out raw materials from nature, modifying nature to create various means of production and subsistence, and giving back waste materials. Labor is an essential moment in this process, and it is a transhistorical and material activity in nature, which Marx also calls “natural force.”37 After comprehending these three moments, Marx then analyzes how this incessant material exchange between humans and nature transforms itself when it receives a specific capitalist function as “valorization process of capital.” This point is the most important aspect, and I will come back to this theme in the next chapter.
In the Grundrisse, there are other meanings of metabolism that Marx continued to use until Capital. “Changes of material (Stoffwechsel = metabolism)” is contrasted with “changes of form (Formwechsel).” “Change of form” signifies exchanges of economic forms between money and commodity during the circulation process—“C-M-C” and “M-C-M”—and “change of material” has to do with the constant changes among use values within capitalist society:
Simple circulation consisted of a great number of simultaneous or successive exchanges.… A system of exchanges, changes of material [Stoffwechsel], from the standpoint of use value. Changes of form [Formwechsel], from the standpoint of 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