Biomedical subjects

Olaf Breidbach

Publications and source records attributed to Olaf Breidbach.

7 recordsLinked to original sources

PubMed2006

On the gestalt concept.

We define a gestalt as the invariants of a collection of patterns that can mutually be transformed into each other through a class of transformations encoded by, or conversely, determining that gestalt. The class of these transformations needs to satisfy structural regularities like the ones of the mathematical structure of a group. This makes an analysis of a gestalt possible in terms of relations between its representing patterns. While the gestalt concept has its origins in cognitive psychology, it has also important implications for morphology.

Cognition↗

PubMed2006

The conceptual framework of evolutionary morphology in the studies of Ernst Haeckel and Fritz Müller.

In his Gastraea studies Ernst Haeckel characterized the initial stages of the animal embryo, describing complete and incomplete cleavages in various groups, until the gastrula stage. Thereby, he was able to point out various degrees of developmental diversification in these initial stages of development. As the functional meaning of such cleavages was not clear however, it was difficult to argue about putative functional adaptations. Information about the consequences for tissue formation initiated in this primary phase of development was simply lacking. Haeckel could only provide a vague picture of a highly diversified but systematically inconsistent distribution of various types of early embryogenesis. Thereby he discusses phylogenetically preserved (palingenetic) stages of development and adaptations to certain specific situations of the embryo (cenogenesis). To decide whether such types, in the initial stages of embryogenesis, are ceno- or phaenogenetic is quite difficult. Reference to the highly diversified distribution of certain types within specific groups is an indication that there is no strict adaptive pressure on these early parts of embryonic development. This makes it possible to formulate - as Haeckel did it - the idea, that in these initial phases palingenetic attributes are dominant. Thus, he tried to use these early phases of development for the classification of larger systematic units. The result is a concept of an evolutionary morphology, that was, however, never elaborated in detail by Haeckel. Therefore, it remained without effect for evolutionary biology. On the contrary, following the Darwinian approach towards a comparative analysis of embryogenesis, Fritz Müller presented a series of examples for a comparative developmental biology that allowed one to interpret certain morphological characteristics as the outcome of common evolutionary histories within different species. For various crustacean species, he was able to demonstrate that certain attributes are not to be characterized as functionally relevant adaptations, but are evolutionarily inherited.

Animals↗

PubMed2005

[Silhouettes: electron microscopic photography in bioscience].

The paper describes the first attempts of biological electron microphotography. It starts with a description of the early use of electron microscopy in biology, showing that electron microscopy was used as an extension of former light microscopical studies. Thus, the pictures produced by electron microscopy are interpreted as describing the micro-texture of those structures already seen in light microscopy. That was done irrespective from the specific problems of tissue preparation for electron microscopy. The use of photography in electron microscopy is discussed in more detail. It is shown that in electron microscopy, not the preparation itself which is usually destroyed or damaged during observation in the electron microscope. Thus, biological electron microscopy can be described as a real image science.

Biology↗

PubMed2004

[Reception of research in the natural sciences in middle Germany at the Padua University betwee 1770 and 1820].

The German literature on natural sciences that was present in the public libraries in Padua between 1770 and 1820 is described. The citations of German authors in the publications of Paduan naturalists of that time and of the textbooks used in Padua University are outlined. German journals on natural sciences available in Venice and Padua and Italian translations of German monographs of that time are also documented. With the foundation of the Italian Empire by Napoleon, the organization of lectures and research in the University of Padua changed drastically. In consequence, the reception of chemistry and physics was exclusively directed to France. In the descriptive natural sciences the earlier German traditions prevailed. Therein, however, Paduan sciences adopted the earlier descriptive traditions that already existed at the end of the 18th century and did not respond to the new developments in German functional morphology and physiology. Jenensian naturalists, botanists and physicists who received attention in Padua around 1800 are described as part of the empiric tradition of Central Germany and not as followers of the speculative "Naturphilosophie". There is no explicit reference to romantic sciences.

Education, Medical↗

PubMed2004

[Schelling and experiential science].

Schelling's philosophy of nature is shown to be part of the scientific discussions of his day, not set apart from it. His terminology describing the potentialities and polarities of nature was formed during Schelling's collaboration with the physicist Johann Wilhelm Ritter. This scientist adopted the schema Schelling had developed for the categorization of natural phenomena to describe the peculiar facts that interested him in his area of research. Thus Ritter was able to develop a classification of the various phenomena of animal galvanism. Thus it can be shown that the idealistic "Naturphilosophie" was part of the scientific culture of about 1800. It is to be interpreted as philosophy of science and has to be evaluated not only in a philosophically systematic way but in particular in its influence on the way scientific categories were ordered at the time. Thereby it can be shown that the idealistic vocabulary had close correspondence to French morphology and English Natural Theology.

Animals↗

PubMed2002

Representation of the microcosm: the claim for objectivity in 19th century scientific microphotography.

Microphotography was one of the earliest applications of photography in science. The first monograph on tissue organization illustrated with microphotographs was published in 1845. In the 1860s, a large number of introductions to scientific microphotography was published by anatomists. They argued that microphotography was a means of documenting the results of microscopic analysis, uncontaminated by subjectivity of the observer. In the early decades of the 19th century, before the general acceptance of cell theory, such a technique was of special importance, so no criteria were available to distinguish between important and superficial characters in the description of tissue microstructures. Microphotography was praised as the method of choice for documenting the scientific observations of microscopic material. Some of the microphotographic practices described in these early manuals, however, did not conform with the idea of a purely mechanical process of documentation. The authors of these manuals saw photography not as a technique which produced artifacts, but as a complete and reliable substitute for the original preparations. Thus, according to these authors, the artificial world of photography was seen as the actual representation of the microworld. Consequently, they tried to understand the microcosm by analyzing photographs instead of the microscopic preparation themselves. Such attitudes discredited the use of microphotography in the sciences. Consequently, the definitive breakthrough of scientific microphotography was delayed until the 1880s and was largely due to the efforts of Robert Koch, who made microphotography a central tool of bacteriology.

Bacteriology↗

PubMed2002

Lorenz Oken and Naturphilosophie in Jena, Paris and London.

Although Lorenz Oken is a classic example of Naturphilosophie as applied to biology, his views have been imperfectly understood. He is best viewed as a follower of Schelling who consistently attempted to apply Schelling's ideas to biological data. His version of Naturphilosophic, however, was strongly influenced by older pseudoscience traditions, especially alchemy and numerology as they had been presented by Robert Fludd, whose works were current in Jena and available to him. According to those influences, parts of Oken's philosophical conception were communicable even in a non-idealistic scientific culture, for example in Paris, where Oken met Etienne Geoffroy Saint-Hilaire. Geoffroy however was embedded in a French intellectual tradition, and the correspondence between his views and those of Oken was only superficial. The English anatomist Richard Owen attempted to incorporate the views of Oken and Geoffroy within his own, idiosyncratic system. Although Darwin knew of Oken's ideas, it was Geoffroy who really affected his evolutionary biology, and any influence of Oken must have been attenuated to the point of triviality.

Biology↗