In 1853, the young Thomas Henry Huxley published a long review of German cell theory in which he roundly criticized the basic tenets of the Schleiden-Schwann model of the cell. Although historians of cytology have dismissed Huxley's criticism as based on an erroneous interpretation of cell physiology, the review is better understood as a contribution to embryology. "The Cell-theory" presents Huxley's "epigenetic" interpretation of histological organization emerging from changes in the protoplasm to (...) replace the "preformationist" cell theory of Schleiden and Schwann (as modified by Albert von Kölliker), which posited the nucleus as the seat of organic vitality. Huxley's views influenced a number of British biologists, who continued to oppose German cell theory well into the twentieth century. Yet Huxley was pivotal in introducing the new German program of "scientific zoology" to Britain in the early 1850s, championing its empiricist methodology as a means to enact broad disciplinary and institutional reforms in British natural history. (shrink)

(Recipient of the 2020 Everett Mendelsohn Prize.) This article revisits the development of the protoplasm concept as it originally arose from critiques of the cell theory, and examines how the term “protoplasm” transformed from a botanical term of art in the 1840s to the so-called “living substance” and “the physical basis of life” two decades later. I show that there were two major shifts in biological materialism that needed to occur before protoplasm theory could be elevated to (...) have equal status with cell theory in the nineteenth century. First, I argue that biologists had to accept that life could inhere in matter alone, regardless of form. Second, I argue that in the 1840s, ideas of what formless, biological matter was capable of dramatically changed: going from a “coagulation paradigm” that had existed since Theophrastus, to a more robust conception of matter that was itself capable of movement and self-maintenance. In addition to revisiting Schleiden and Schwann’s original writings on cell theory, this article looks especially closely at Hugo von Mohl’s definition of the protoplasm concept in 1846, how it differed from his primordial utricle theory of cell structure two years earlier. This article draws on Lakoff and Johnson’s theory of “ontological metaphors” to show that the cell, primordial utricle, and protoplasm can be understood as material container, object, and substance, and that these overlapping distinctions help explain the chaotic and confusing early history of cell theory. (shrink)

The cell theory of Schleiden and Schwann is generalized to the effect that throughout the natural world, in physics, biology, and sociopsychology, there is a widespread phenomenon of the existence of organized cells, whose organization is usually protected by barriers. These barriers exist not only in space, but in time and even in other domains. These barriers typically not only protect the organization within the cell from external disturbance, but they actively participate in reducing the (...) internal disorganization. It appears that the quantum phase cell or its equivalent, the discrete quantum state, may be a physical analog of the organized biological cell. The sampling and ambiguity theorems of communication theory throw new light on phase cells. The quantum phase cell has both configuration and momentum elements, which are analogous respectively to the somatic elements in the cytoplasm of a cell and the genetic elements in the DNA. A biological cell or organism, a physical quantum state, and a human being as a sociopsychological entity each has a natural individuality. A natural individuality is a somewhat mysterious thing, since in addition to specificity, it also involves stochasticity and complementarity. There are some striking and unexplained spin-analog characteristics in biology which have a relation to boson- and fermion-analog characteristics in biology that corresponds with the known relation in physics. The hypothesis suggested in our earlier paper, that quantum mechanical entropy is diminished in interaction, is clarified and sharpened in this paper. (shrink)

The cell is not only the structural, physiological, and developmental unit of life, but also the reproductive one. So far, however, this aspect of the cell has received little attention from historians and philosophers of biology. I will argue that cell theory had far-reaching consequences for how biologists conceptualized the reproductive relationships between germs and adult organisms. Cell theory, as formulated by Theodor Schwann in 1839, implied that this relationship was a specific and (...) lawful one, that is, that germs of a certain kind, all else being equal, would produce adult organisms of the same kind, and vice versa. Questions of preformation and epigenesis took on a new meaning under this presupposition. The question then became one of whether cells could be considered as autonomous agents producing adult organisms of a given species, or whether they were the product of external, organizing forces and thus only a stage in the development of the whole organism. This question became an important issue for nineteenth-century biology. As I will demonstrate, it was the view of cells as autonomous agents which helped both Charles Darwin and Gregor Mendel to think of inheritance as a lawful process. (shrink)

The cell is not only the structural, physiological, and developmental unit of life, but also the reproductive one. So far, however, this aspect of the cell has received little attention from historians and philosophers of biology. I will argue that cell theory had far-reaching consequences for how biologists conceptualized the reproductive relationships between germs and adult organisms. Cell theory, as formulated by Theodor Schwann in 1839, implied that this relationship was a specific and (...) lawful one, that is, that germs of a certain kind, all else being equal, would produce adult organisms of the same kind, and vice versa. Questions of preformation and epigenesis took on a new meaning under this presupposition. The question then became one of whether cells could be considered as autonomous agents producing adult organisms of a given species, or whether they were the product of external, organizing forces and thus only a stage in the development of the whole organism. This question became an important issue for nineteenth-century biology. As I will demonstrate, it was the view of cells as autonomous agents which helped both Charles Darwin and Gregor Mendel to think of inheritance as a lawful process. (shrink)

This bibliographical review of the modelling of the mitotic apparatus covers a period of one hundred and twenty years, from the discovery of the bipolar mitotic spindle up to the present day. Without attempting to be fully comprehensive, it will describe the evolution of the main ideas that have left their mark on a century of experimental and theoretical research. Fol and Bütschli's first writings date back to 1873, at a time when Schleiden and Schwann's cell (...) class='Hi'>theory was rapidly gaining ground throughout Germany. Both mitosis and chromosomes were to be discovered within the space of thirty years, along with the two key events in the animal and plant reproductive cycle, namely fecondation and meiosis. The mitotic pole, a term still in use to this day, was employed to describe a morphological fact which was noted as early as 1876, namely that the lines and the dots of the karyokinetic figure, with its spindle and asters, looks remarkably like the lines of force around a bar magnet. This was to lead to models designed to explain the movements of chromosomes which take place when the cell nucleus appears to cease to exist as an organelle during mitosis. The nature of those mechanisms and the origin of the forces behind the chromosomes' ordered movements were central to the debate. Auguste Prenant, in a remarkable bibliographical synthesis published in 1910, summed up the opposing viewpoints of the vitalists, on the one hand, who favoured the theory of contractility or extensility in spindle fibres, and of those who believed in models based on physical phenomena, on the other. The latter subdivided into two groups: some, like Bütschli, Rhumbler or Leduc, referred to diffusion, osmosis and superficial tension, whilst the others, led by Gallardo and Hartog, focussed on the laws of electromagnetism. Lillie, Kuwada and Darlington followed up this line of research. The mid-20th century was a major turning point. Most of the modelling mentioned above was criticized and fell into disuse after disappearing from research publications and textbooks.This marked the onset of a new era, as electron microscopes made possible the materialization and detailed study of the macromolecular elements of the fibres, filaments and microtubules of the cytoskeleton. The successive phases of (a) de Harven and Bernhard's 1956 discovery of the centriole's ultrastructure, (b) its identification with the basal body of the cilia and flagella, confirming the theory set out by Henneguy and von Lenhossek (1898–99), (c) the universal presence of microtubules in animal, vegetal and eukaryotic protist cells, (d) the polymerization-depolymerization induced reversible transformations of the tubulin pool in mitosing cells (Inoue, 1960), (e) ultrastructural comparative studies of the mitotic apparatus of eukaryotes illustrating the Pickett-Heaps integrating concept of the MTOC (microtubule-organizing centre), (f) the possibility ofin vitro experiments on mtocs or on microtubules, brings us upon the present day, which has seen the focus placed on the concept of motor-proteins (kinesin, dynein) and on cell cycle models. The latter are based on a close coincidence between the observable modifications of the mitotic apparatus and the periodic variations in intracellular concentrations of calcium or of certain enzymes (cyclins, Cdc2) during the main transitions of the cell cycle. (shrink)

What is the relation between things and theories, the material world and its scientific representations? This is a staple philosophical problem that rarely counts as historically legitimate or fruitful. In the following dialogue, the interlocutors do not argue for or against realism. Instead, they explore changing relations between theories and things, between contested objects of knowledge and less contested, more everyday things. Widely seen as the life sciences' first general theory, the cell theory underwent dramatic changes during (...) the nineteenth century. The dialogue establishes that each successive version of the cell theory was formulated -- each identity of the object cell was formed -- around a different material : cork, cartilage, eggs in cleavage, muscle. Such things thus serve as exemplary materials, in ways not described by standard concepts like induction, theory -testing, theory -laden observation, and construction. Still, how can theories and perspective possibly be honed on things if these are apprehended differently by different observers according to their interests, training, culture, or indeed theories? The second part of the dialogue addresses this problem, partly through the verbal and visual schemata that were used by nineteenth-century microscopists and that are comparable to schemata in the visual arts. The third part of the dialogue considers the exemplary materials as a historical sequence, itself needing explanation. Theoretical change devolved partly from wider histories and geographies of the prevalence, availability, or scientific and cultural status of materials such as plants, animals, and muscle. (shrink)

The ArgumentMicroscopical consideration played a crucial role in German physiology in the period of, grosso modo, 1780–1830. Specifically, a conception of material change was established, according to which all life is grounded in the process of the generation of microscopical forms out of an amorphous, primitive generative substance. Embryological development, tissue growth, and the generation of microorganisms were all considered to be the manifestation of this fundamental developmental process. In contrast to the common historiography, I try to understand Theodor (...) class='Hi'>Schwann's 1838 discovery of the cell theory in terms of the epistemological categories he applied to the prevailing conceptions of life and living matter. I argue that Schwann was able to discern cells not because of any superior microscopical methods, but rather as part of his wider investigative endeavor to explicate life processes according to specific causal agents. I argue that Schwann was able to demonstrate the existence of cells only when he considered animal tissues in terms of a causal relation between specific material agents and their effect, that is, the developmental history of tissue. (shrink)

The Liver kinase B1 with its downstream target AMP activated protein kinase (LKB1‐AMPK), and the key nutrient sensor mammalian target of rapamycin complex 1 (mTORC1) form two signaling systems that coordinate metabolic and cellular activity with changes in the environment in order to preserve homeostasis. For example, nutritional fluctuations rapidly feed back on these signaling systems and thereby affect cell‐specific functions. Recent studies have started to reveal important roles of these strategic metabolic regulators in Schwann cells for the (...) trophic support and myelination of axons. Because aberrant intermediate metabolism along with mitochondrial dysfunction in Schwann cells is mechanistically linked to nerve abnormalities found in acquired and inherited peripheral neuropathies, manipulation of the LKB1‐AMPK, and mTORC1 signaling hubs may be a worthwhile therapeutic target to mitigate nerve damage in disease. Here, recent advances in our understanding of LKB1‐AMPK and mTORC1 functions in Schwann cells are covered, and future research areas for this key metabolic signaling network are proposed. (shrink)

Biological atomism postulates that all life is composed of elementary and indivisible vital units. The activity of a living organism is thus conceived as the result of the activities and interactions of its elementary constituents, each of which individually already exhibits all the attributes proper to life. This paper surveys some of the key episodes in the history of biological atomism, and situates cell theory within this tradition. The atomistic foundations of cell theory are subsequently dissected (...) and discussed, together with the theory’s conceptual development and eventual consolidation. This paper then examines the major criticisms that have been waged against cell theory, and argues that these too can be interpreted through the prism of biological atomism as attempts to relocate the true biological atom away from the cell to a level of organization above or below it. Overall, biological atomism provides a useful perspective through which to examine the history and philosophy of cell theory, and it also opens up a new way of thinking about the epistemic decomposition of living organisms that significantly departs from the physicochemical reductionism of mechanistic biology. (shrink)

According to scientific procedure, each discipline first describes the phenomena of its research area, then analyzes them, and tinally categorizes them in a system. To date, biology has lacked such a system for its smallest building blocks, the cells. Although the theory of evolution explains certain central evolutionary mechanisms of the cell, there existed no generally accepted theory of the organization of the cell. The endoeytobiotic cell theory is suggested as a possible basis for (...) a satisfying explanation of the structure, function, information, and evolution of the cell. Furthermore, a hypothetical periodic system of the cell is developed. This system consists of eight groups, including the ecological niches fermentation, respiration, photergy, and photosynthesis (each aerobic and anaerobic) and seven periods with increasing numbers of protein biosynthesis machineries (cytoplasma, mitochondria, plastids, endocytobionts). We find furthermore, a division according to typical animal or plant cells and between these two in fungus-like cells. (shrink)

With historical hindsight, it can be little questioned that the view of protozoa as unicellular organisms was important for the development of the discipline of protozoology. In the early years of this century, the assumption of unicellularity provided a sound justification for the study of protists: it linked them to the metazoa and supported the claim that the study of these “simple” unicellular organisms could shed light on the organization of the metazoan cell. This prospect was significant, given the (...) state of cytology circa 1910. In the wake of the major gains made in understanding nuclear division in the last two decades of the nineteenth century, cytology was suddenly confronted with many, seemingly less penetrable, problems. Several aspects of nuclear organization still remained unexplained, and recent research had revealed the presence in the cytoplasm of structures whose functions in cell life were unknown. Classical methods of cytology, relying on descriptive, morphological analysis, seemed ill equipped to resolve these questions.Hertwig's program for protozoology, grounded in the assumption of the fundamental unity of organization in protozoa and metazoa, offered a potential means for investigating these and other problems of cell theory. Linked to mainstream cytology, protozoology was advocated as a means of experimentally investigating key biolobical processes — reproduction, metabolism, and organelle morphology and physiology — less accessible in higher organisms. Protozoa were hailed as prime experimental organisms, in which cell structure and function could be more easily studied. Unlike the metazoan cell, they could be subjected to controlled experiments in which the external environment was modified and the effects monitored. Protozoa offered, in other words, a promising experimental means by which to investigate the cell — its structures and its processes.The success of this program within Germany was soon apparent. In contrast to the rather neglected state of the discipline in 1900, protozoology began to be recognized as more than a somewhat obscure area of study for specialists. In practical terms, this translated into greater numbers of students attracted to the field, increased institutional support for the discipline, and its elevation in status within the biological sciences as new developments, particularly in connection with medical applications, began to draw attention to the field.64The unicellular hypothesis also promoted the internal development of the science. It provided a rationale for introducing the various techniques used in cytology, embryology, physiology, and the new field of biochemistry as suitable research tools for protozoology as well. This vastly extended the research possibilities and facilitated the understanding of, among other things, protozoan organization, modes of reproduction, and evolutionary relationships. The new experimental grounding of the discipline in turn fitted in well with developments in biology at large: in contrast to the descriptive methodology that had predominated in the nineteenth century, this new experimental program placed protozoology at the forefront of the early twentieth-century movement to make biology an experimental science comparable to physics and chemistry.Yet the criticism of the unicellular hypothesis can also be seen as having served a valuable function within the development of the discipline. It focused attention on the study of protists as organisms in their own right, not simply as models for metazoan cells. More generally, it helped to remind biologists of the particular evolutionary assumptions that supported this conception. Dobell and other British critics pointed out, among other things, the association between the theory of recapitulation and the interpretation of protozoa as unicellular organisms. At the time when the recapitulation theory and the germ-layer doctrine were in decline, it was important to stress how these evolutionary ideas also entered into the contemporary concepts of subsidiary specialties. This was as true for protozoology as it was for cell theory itself. The chromidial theory, in its various guises, and the binuclearity hypothesis did in fact contain elements of recapitulationist reasoning, and they were open to criticism for the same kind of overly speculative theorizing that characterized this evolution theory. Dobell's critique forced protozoologists and cell theorists alike to review the theoretical postulates guiding their investigations.In the absence of further historical studies, it is hard to evaluate the consequences of this debate in later years. The issue was not whether protozoa were the precursors of metazoa — both sides accepted this. They disagreed over which particular protozoon had served as the ancestral form, and this, in turn, influenced their stance on the question of unicellularity. The situation is little changed today. Because the former question is still an open one, the latter remains so too. Both of the models for the origin of multicellular organisms — colonies of ciliates versus multinucleate protists — are still presented as possible mechanisms in modern textbooks of evolution. Unable to judge the dispute in terms of the ultimate validity of the competing conceptions, the historian requires other criteria. It perhaps becomes more important to evaluate the issues in the context of the internal and external stimulus they provided the discipline.65 In these terms, and from the present historical vantage point, Hertwig's research program for protozoology, based upon the unicellular hypothesis, appears to have been a successful one. (shrink)

Introduction A Brief Conceptual Framework for Biology PART ONE: UNDERSTANDING NATURE 1. The Antecedents of Scientific Thought Animism, Totemism, and Shamanism The Paleolithic View Mesopotamia Egypt 2. Aristotle and the Greek View of Nature The Science of Animal Biology The Parts of Animals The Classification of Animals The Aristotelian System Basic Questions 3. Those Rational Greeks? Theophrastus and the Science of Botany The Roman Pliny Hippocrates, the Father of Medicine Erasistratus Galen of Pergamum The Greek Miracle 4. The Judeo-Christian Worldview (...) The Bishop of Hippo Scholastic Thought Islamic Science Books on Beasts Antecedents of a Revolution 5. The Revival of Science Andreas Vesalius and the Study of Structure William Harvey and the Study of Function Sir Francis Bacon’s Great Instauration Induction, Hypothesis, Deduction The Very Small--Animalcules Robert Hooke and the Discovery of Cells 6. Figur’d Stones and Plastick Virtue Marine Life on Mountain Tops? Figured Stones of Unknown Creatures Baron Cuvier Quarries of the Paris Basin Catastrophism and Uniformitarianism William Smith and the Geological Column Understanding Nature in 1850 PART TWO: THE GROWTH OF EVOLUTIONARY THOUGHT 7. The Paradigm of Evolution First Questions The Paradigm of Natural Theology First Answers 8. Testing Darwins Hypotheses Have Life Forms Changed over Time? Do Species Evolve into Different Species over Time? Has There Been Time Enough for Evolution? Is Natural Selection the Mechanism of Change? The Genetic Basis of Natural Selection Accounting for the Diversity of Life 9. In the Light of Evolution Comparative Anatomy Embryonic Development Classification Microstructure Molecular Processes 10. Life over Time The Origin of Life The Rise of Multicelled Organisms What Is a Phylum? Burgess Shale Metazoans Early Evolution of the Vertebrates The Age of Dinosaurs Birds, Mammals, and Flowering Plants The Rancho La Brea Tar Pits Human Evolution The Role of Extinction in Evolution PART THREE: CLASSICAL GENETICS 11. Pangenesis What Is the Question? Hippocrates and Aristotle The Darwinian Answer Assembling the Data Formulating the Hypothesis by Induction Galton’s Rabbits 12. The Cell Theory The Discovery of Cells: Robert Hooke Schwann and Cells in Animals Gametes as Cells Omnis cellula e cellula? The Technology of Cell Research 13. The Hypothesis of Chromosomal Continuity The Ephemeral Nucleus Schneider, Flemming, and Cell Division The Chromosomes and inheritance Gamete Formation Fertilization 14. Mendel and the Birth of Genetics Model for Monohybrid Crosses Model for Dihybrid Crosses Mendel’s Laws Initial Opposition to Mendelism 15. Genetics + Cytology: 1900-1910 Sutton’s Model The Cytological Basis of Mendel’s Laws Boveri and Abnormal Chromosome Sets Variations in Mendelian Ratios The Discovery of Sex Chromosomes 16. The Genetics of the Fruit Fly Morgan’s First Hypothesis Morgan’s Second Hypothesis The Fly Room Linkage and Crossing-Over The Cytological Proof of Crossing-Over Mapping the Chromosomes The Final Proof The Determinants of Sex The Conceptual Foundations of Classical Genetics 17. The Structure and Function of Genes One Gene, One Enzyme The Substance of Inheritance The Watson-Crick Model of DNA Genes and the Synthesis of Proteins The Genetic Code PART FOUR: THE ENIGMA OF DEVELOPMENT 18. First Principles The Peripatetic Stagirite The Death and Rebirth of Scientific Thought Harvey and Malpighi A Two-Millennial Summing Up Preformation versus Epigenesis 19. The Century of Discovery Von Baer’s Discovery of the Mammalian Ovum Darwin’s Contribution to Embryology Haeckel and Recapitulation 20. Descriptive Embryology Germ Layers The External Development of the Amphibian Embryo The Internal Development of the Amphibian Embryo 21. The Dawn of Analytical Embryology His, Roux, and Mosaic Development Driesch and Regulative Development Novelty in Development Cell Lineage Nucleus or Cytoplasm? Fin de Siècle 22. Interactions during Development Amphibian Organizers Secondary Organizers The Reacting Tissue The Chemical Nature of the Organizer Putting It All Together Conclusion Further Reading References Illustration Credits Index. (shrink)

In a review of the cell biology and heredity studies of 1900–1910, Bernardino Fantini argues that the choice of an experimental subject or organism was crucial in opening up new discoveries and new theories for specific fields of research.69 Thinking on a broader level, Bütschli expressed a similar view when he stated that an understanding of the true nature and structure of the “elementary organism” was crucial to the whole of biology. In this article we have traced the impact (...) of Bütschli's unicellular model of protozoa up to the general acceptance of the eukaryotic cell as nature's primary organism. We have also seen that Bütschli's vision in the Studien gave birth to Protistenforschung and Zellforschung, sister sciences whose task it was to further and integrate knowledge of the living cell. Of necessity, we have confined ourselves to German scientific developments. However, our attempt to recapture and define the unity and meaning of a biology of the “cell-microcosm” has given us pause to reconsider the development and nature of Wilhelmian biological science. (shrink)

Edmund Beecher Wilson is generally celebrated for his contribution to chromosome theory and genetics, whereas opinion concerning his cytological thinking is often restricted to the idea that he provided evidence for the dominant role of the nucleus. But Wilson's cell theory was much more. It was a child of the German Zellforschung, and its attempt to provide a comprehensive cellular answer to a wide range of biological and physiological questions. Wilson developed a corpuscular, micromeristic and preformistic concept, (...) and treated the cell as an organism subject to ontogenetic and phylogenetic processes. He defended his comprehensive theory even in the 1920's, when cytological research had become specialised and directed at more practical goals. For many of his younger readers this concept might have seemed antiquated, but today many of its features sound surprisingly modern. (shrink)

In this paper we develop a differential analogue of o-minimal cell decomposition for the theory CODF of closed ordered differential fields. Thanks to this differential cell decomposition we define a well-behaving dimension function on the class of definable sets in CODF. We conclude this paper by proving that this dimension is closely related to both the usual differential transcendence degree and the topological dimension associated, in this case, with a natural differential topology on ordered differential fields.

In 1877, the young Alfred Espinas defended a philosophical study, ‘doctorat ès lettres’, at the Sorbonne University, entitled Des Sociétés animales. This was to become one of the principal sources of French organicist sociology. The paradox, however, is that this work seems to be fundamentally a study of natural science. Espinas tried to justify his position theoretically through two types of reciprocally exclusive and uncomplementary arguments. The first one consists in showing that only certain kinds of animal groupings belong legitimately, (...) if not academically, to sociology. The second one has a greater audacious and uncontrollable dimension. It consists in asserting that all pluricellular organisms are true societies. In this article we first focus on the role played by cellular theory in such a ‘sociologization’ of biology, concerning the extension of sociology. Second, we examine the importance of such confusion within the fields of extension, in aiming to explain the conceptual transfers between social sciences and life sciences, in the second half of the 19th century. (shrink)

La« théorie cellulaire», élaborée au XIXe siècle sous l'impulsion, entre autres chercheurs, de Lorenz Oken, Matthias Schleiden, Theodor Schwann et Rudolf Virchow, a profondément modifié la vision que l'Homme se faisait jusque-là de la vie, puisqu'elle affirmait que la cellule est l'unité organique constitutive de tous les êtres vivants et que tout être vivant est issu d'une cellule. L'observation d'un unicellulaire comme la paramécie montre, en effet, qu'une cellule doit être considérée comme une forme vivante intégrale puisqu'en se (...) nourrissant, en se développant, en se défendant et en se reproduisant elle manifeste le destin commun à tous les êtres vivants. Son espace vital, engendré par ses déplacements, est coextensif à ses besoins et donc à ses comportements. (shrink)

What are cells? How are they related to each other and to the organism as a whole? These questions have exercised biology since Schleiden and Schwann (1838–1839) first proposed cells as the key units of structure and function of all living things. But how do we try to understand them? Through new technologies like the achromatic microscope and the electron microscope. But just as importantly, through the metaphors our culture has made available to biologists in different periods and (...) places. These two new volumes provide interesting history and philosophy of the development of cell biology. Reynolds surveys the field's changing conceptual structure by examining the varied panoply of changing metaphors used to conceptualize and explain cells – from cells as empty boxes, as building blocks, to individual organisms, to chemical factories, and through many succeeding metaphors up to one with great currency today: cells as social creatures in communication with others in their community. There is some of this approach in theVisionsedited collection as well. But this collection also includes rich material on the technologies used to visualize cells and their dialectical relationship with the epistemology of the emerging distinct discipline of cell biology. This volume centres on, but is not limited to, ‘reflections inspired by [E.V.] Cowdry's [1924 volume]General Cytology’; it benefits from a conference on the Cowdry volume as well as a 2011 Marine Biological Lab/Arizona State University workshop on the history of cell biology. (shrink)

Division of labour is a marked feature of multicellular organisms. Margulis proposed that the ancestors of metazoans had only one microtubule organizing center (MTOC), so they could not move and divide simultaneously. Selection for simultaneous movement and cell division had driven the division of labour between cells. However, no evidence or explanation for this assumption was provided. Why could the unicellular ancetors not have multiple MTOCs? The gain and loss of three possible strategies are discussed. It was found that (...) the advantage of one or two MTOC per cell is environment-dependent. Unicellular organisms with only one MTOC per cell are favored only in resource-limited environments without strong predatory pressure. If division of labour occurring in a bicellular organism just makes simultaneous movement and cell division possible, the possibility of its fixation by natural selection is very low because a somatic cell performing the function of an MTOC is obviously wasting resources. Evolutionary biologists should search for other selective forces for division of labour in cells. (shrink)

Empirical evidence suggests that high frequency electrographic activity is involved in active representation of meaningful entities in the cortex. Theoretical work suggests that distributed cell assemblies also represent meaningful entities. However, we are still some way from understanding how these two are related. This commentary also makes suggestions for further investigation of the neural basis of language at the level of both words and sentence planning.

A fundamental claim associated with parallel distributed processing theories of cognition is that knowledge is coded in a distributed manner in mind and brain. This approach rejects the claim that knowledge is coded in a localist fashion, with words, objects, and simple concepts, that is, coded with their own dedicated representations. One of the putative advantages of this approach is that the theories are biologically plausible. Indeed, advocates of the PDP approach often highlight the close parallels between distributed representations learned (...) in connectionist models and neural coding in brain and often dismiss localist theories as biologically implausible. The author reviews a range a data that strongly challenge this claim and shows that localist models provide a better account of single-cell recording studies. The author also contrast local and alternative distributed coding schemes and argues that common rejection of grandmother cell theories in neuroscience is due to a misunderstanding about how localist models behave. The author concludes that the localist representations embedded in theories of perception and cognition are consistent with neuroscience; biology only calls into question the distributed representations often learned in PDP models. (shrink)