The metabolic code constitutes still another fascinating set of endosemiotic properties, because, as Tomkins
(1975) showed in his brilliant article completed just prior to his death, complex regulation is characterized by two
entities not operating in simple mechanisms: these are metabolic symbols and their domains, where the former "refers
to a specific intracellular effector molecule which accumulates when a cell is exposed to a particular environment"
(ibid.:761). For example, cyclic adenosine monophosphate (cAMP) acts, in most micro-organisms, as a symbol for
carbon-source starvation, or ppGpp acts as a symbol for nitrogen or amino acid deficiency. Without going into
details, the conspicuous point to note here is that, while a simple regulatory mode, that is, a direct chemical
relationship between regulatory molecules and their effects, is a clear instance of Peirce's "secondness, or
dependence," the complex mode is an instance of "thirdness, or mediation" (3-422). This insight was foreshadowed
by Peirce himself in his observation that a "rhema is somewhat closely analogous to a chemical atom" (3-421).
Tomkins's reasoning (1975:761) is highly semiotized: "Metabolic symbols need bear no structural relationship to the
molecules which promote their accumulation," and, since a particular environmental (or contextual) condition is
correlated with a corresponding intracellular symbol, the imputed "relationship between the extra- and intracellular
events may be considered as a 'metabolic code' in which a specific symbol represents a unique state of
The endocrine and the nervous systems, as noted above, are intimately fastened together via signs. As for the
neural code itself, semiosis is what neurobiology is all about. "The modes of communication include membrane
conductances, patterns of neural spikes and graded potentials, electric coupling between cells, electrical and chemical
transmission at synapses, secretion, and modification of neural function" (Prosser 1985: 118). The basic principle
for understanding most sign use by neurons comes down to the selective permeability of their plasma membrane to
ions (charged atoms), which seem to penetrate through specific pores, or channels, in the membrane. Another newly
labeled interfacial field of research is "neurocommunications," which aims to portray in a current jargon the (human)
mind, or "software level," and brain, or "hardware level," as a pair of semiotic coupled engines, namely,
computational devices for verbal-nonverbal sign processing.
Beyond endosemiotics, the literature of biosemiotics distinguishes among phyto-, cyto-, and zoosemiotics, the
latter comprising a specially marked branch, anthroposemiotics, to reflect its predominantly glottocentric emphasis,
amounting at times to an obsession. These distinctions correspond exactly to the standard classification of eukaryotic
multicellular organisms into the plant, fungus, and animal super-kingdoms, the last including the animal loquens.
The minor tradition I cited above concentrates on anthroposemiotics to the exclusion of all the other divisions;
it excludes, that is, almost all of the rest of nature.