General introduction to cytoplasm.

Abstract

A mere glance at figures 1 and 2 is enough to demonstrate, in a schematic way, how different our present understanding of cell structure is from that of E. B. Wilson, some 40 years ago: while the essential constituents of the cell nucleus were already known, the cytoplasm had an alveolar (or fibrillar) structure, where no cell organelles (besides the centrosomes) could be seen. This over-cautious representation of cytoplasmic structure was due to the fear of fixation and staining artifacts, as a consequence of the work of J. Loeb and his followers on the properties of colloids. Nowadays, we think in terms of macromolecules rather than miscellae, and we have good reasons to think that microscopy can give a fairly accurate picture of cell structure. When I was a student, our professors did not believe in Golgi bodies, in nuclear membranes, in spindle and aster fibres; even mitochondria were considered as possible artifacts. Everything has changed, within a few decades, thanks to the introduction of new techniques: cytochemistry gave us information about the chemical nature of the various cell inclusions which could be stained by the classical methods; electron microscopy clearly demonstrated that mitochondria, Golgi bodies, centrosomes, aster and spindle fibres, etc., really exist. Biochemistry, under the influence of men like D. Keilin, R. Peters, A. Claude, C. de Duve, etc. succeeded in isolating many cell constituents and in analysing them. Thanks to the cooperation of cytochemical, electron microscopical and biochemical methods, a clearer and more dynamic picture of cellular organization and functioning is now emerging. In the present Discussion, biochemists (Sir Rudolph Peters, C. de Duve), biophysicists (Sir John Randall) and biologists will join forces in order to make progress in the field of ‘molecular cytology’, the study of the cell of today and tomorrow.