Abstract

The employment of the cell-concept is examined in the context of some selected cell-theories ; for these cases it is argued that the logical structures of their respective cell-concepts are strongly interrelated, e. g., in some respect the theory of Schwann is an inversion of that of Meyen. Nevertheless, Meyen's theory is distinguished by operating with an idealized cell-structure that is considered to compromise the necessary constituents for maintaining the diverse cell-functions, whereas in Schwann's theory this clear >cell-structure-to-cell-function< relationship is preserved only for the very beginning of cell-formation; the remaining segments of the cell's life-cycle are modelled according to both a natural-historical and a physicochemical atomistic research programme; thus, this hybrid conception cannot be classified to be a pure cell-physiological one. Other cell-theories from between 1840 and about 1900 – among which are the theories of the »Energide« or the »Mikromer« – do not add to the beforehand elucidated logical structure of those earlier concepts. As a complement to all these cell-theoretical conceptions a more precise understanding of protoplasmatic theories may be obtained. Since, basically, they assumed the possibility of a substance endowed with morphogenetic functions they got into the historically well documented conflict with cell-theories relating structure to function. Finally, the four-fold mode of meaning of the cell-concept is summarized and its relevance for fundamental problems in the biological debate or for questions concerning the reality of biological objects is discussed.