It is worth discussing Marx’s first usage of the concept of metabolism, which was not at all referred to in the earlier debates about his ecological perspective. The relevant text is in one of his London Notebooks of March 1851, titled Reflection, which was later published in the MEGA2.19 The date clearly indicates that Marx knew the concept of metabolism before his reading of Liebig’s book in July 1851.
Because of the scant attention the fourth section of the MEGA2 received, the key passages in Reflection about metabolism were not taken into account in the debates. However, the text provides a helpful hint for Marx’s reception of the physiological concept, for he was not studying natural science so intensively then, so it is safe to assume that he took up the concept right before writing Reflection.
The term “metabolic interaction” (Stoffwechsel) appears three times in Reflection:
Unlike ancient society where only the privileged could exchange this or that [item], everything can be possessed by everybody [in capitalist society]. Every metabolic interaction can be conducted by everyone, depending on the amount of money of one’s income that can be transformed into anything: prostitute, science, protection, medals, servants, cringer—everything [becomes a] product for exchange, just like coffee, sugar, and herring. In the case of rank [society], the enjoyment of an individual, his or her metabolic interaction is dependent on a certain division of labor, under which he or she is subsumed. In the case of class [it is dependent] only on the universal means of exchange that he or she can appropriate.… Where the type of income is still determined by the type of occupation, and not simply by the quantity of the universal medium of exchange like today but by the quality of one’s occupation, the relationships, under which the worker can enter into society and appropriate [objects], are severely restricted, and the social organ for the metabolic interaction with the material and mental productions of the society is limited to a certain way and to a particular content from the beginning.20
In Reflection, Marx again explicates his critique of the money system with a method of comparison between various forms of society, revealing the class antagonism hidden under the formally free and equal relationship of the bourgeois society. In order to illuminate the specificity of the mode of appropriation under the monetary system, Marx contrasts the appropriation of products in capitalist society with that in precapitalist societies, comprehending the problem as different ways of organizing the “metabolic interaction.” In this sense, the concept of “metabolic interaction” is clearly used to deal with the transhistorical character of the necessity to organize social production.
Since in the precapitalist societies the appropriation of products took place based on the direct personal and political dominance legitimated by tradition, innate privileges, and violence, the variability of labor was limited to that within a certain “rank,” and thus “the social organ for the metabolic interaction with material and mental productions of society” remained much narrower than in capitalist society. In capitalist society, the appropriation and transfer of products takes place on a much larger scale among the formally free and equal owners of commodities and money. The commodity exchange appears totally free from class conflicts, and the “metabolic interaction” seems to enlarge with an increasing amount of money. Equality and freedom “without class character,” however, soon turns out to be an “illusion.”21 In reality, the quantitative volume of money decides the “enjoyment of an individual, his metabolic interaction,” totally independent of actual concrete needs. Marx points to the brutal fact that the abstract formal equality under the system of money is inverted into the restriction of freedom and equality. To sum up, Marx in Reflection argues that the individual and social “metabolic interaction” in the capitalist mode of appropriation ends up heavily limited, particularly because of the hidden class character of money, so that individuals are thoroughly impoverished and subjugated to the alien power of money independently of their concrete needs.
Marx used the concept of metabolism in Reflection, and not in the earlier part of the London Notebooks. Despite this fact, it is possible to find out the source. Gerd Pawelzig, in his analysis of Marx’s concept of metabolism, offers the information that in February 1851 Marx received from his friend Roland Daniels a manuscript for a book titled Mikrokosmos: Entwurf einer physiologischen Anthropologie.22 Daniels was an “excellent, scientifically educated doctor” according to Marx and Engels, and he was a member of the Communist League.23 His intellectual relationship with Marx was built on a close friendship, and Marx dedicated his book The Poverty of Philosophy to Daniels.
Daniels wrote to Marx in a letter of February 8, 1851, asking for a “sharp and candid” critique of his manuscript.24 As he explained in his next letter, the principal aim of his Mikrokosmos was to ground, in contrast to the spiritualist theory, “the possibility” to understand “human society in a materialist manner,” based on a “physiological description of activity.”25 Daniels conveyed to Marx that he was attempting to apply the newest physiological knowledge in order to treat the material and mental activity of humans on both individual and social levels as an object of (materialist) scientific investigation. In this context metabolism played an important role. Notably, Daniels used the term in his very first letter to Marx: “I would risk my organic metabolism against a mental metabolism, and I doubt if I would be able to digest and assimilate so many things well to reproduce something ordinary.”26
Marx carefully studied Daniels’s manuscript in the next month and commented on it critically, as Daniels had asked in his letter dated March 20.27 The first usage of the concept of “metabolism” in Reflection is certainly closely connected with his critique of Daniels’s Mikrokosmos, as both texts were written in the same month. Pawelzig was nonetheless not conscious of the relevant paragraph in Reflection and simply concluded that Marx and Engels in 1851 did not use the term metabolism in their notes and letters.28 But this statement is incorrect.
In Daniels’s Mikrokosmos, the concept of “organic metabolism” appears many times. For instance, he defines it as “simultaneous destruction and regeneration, through which these bodies maintain their individuality as they incessantly and newly produce this individuality—this is a uniqueness whose analogy cannot be found in inorganic bodies.”29 Though there is some affinity between Daniels and Liebig in their treatment of metabolism, Daniels’s discussion displays his originality when he divides “organic metabolism” into “animal and mental metabolism” and criticizes the ungrounded supposition of “vital force.”30 His materialist understanding of mental metabolism is directed both against the philosophical dualism of “body” and “spirit” and against the Hegelian speculative philosophy of “absolute spirit.”31 Nonetheless, Daniels’s materialist orientation tends toward a naïve materialism because he interprets human thought, freedom, and history as pure “nerve physiological” phenomena.32 Even if Daniels, in accordance with Marx’s German Ideology, sometimes demands historical explanation through an analysis of “each type of production of material needs of life,” he tends to reduce all dimensions of human activities to a compound of pure physiological—and thus totally ahistorical—“reflex movement” that functions independently of historical production. Consequently, his theory turns out to be mechanistic and deterministic. Marx was not really content with Daniels’s Mikrokosmos, as he reported to Engels: “What little sense there is in his letter is a reflection of my own to him.”33
Marx’s critique of Daniels does not mean that he entirely dismissed the importance of the manuscript. Daniels’s replies to Marx’s criticisms indicate that he patiently provided him with critical comments and explanations to his questions. Even if Marx did not accept the general direction of Daniels’s materialist project, intensive discussions between them prompted Marx to use the concept of metabolism in his private notes in Reflection, and he came to be more interested in physiology, as documented in the London Notebooks after July 1851, most notably in excerpts from Liebig’s work. Marx shared an opinion with Daniels that the new physiological concept could