Intermediate Picture Research Articles

Le problème de l'ultrastructure du cytoplasme et des artéfacts de fixation: Étude sur les leucocytes et les plaquettes sanguines au microscope électronique

The action of about 30 usual fixatives on the ultrastructure of the leucocytes and the thrombocytes of human blood was systematically studied. It was found that in spite of their different mode of action the pictures were comparable showing mostly a fibrillary cytoplasmic network of submicroscopical dimensions. The fixatives were divided into 2 groups according to the dimensions of this network: those which “reduce” or even completely suppress (e.g., osmium acid, formol), those which on the contrary exaggerate it more or less (e.g., chromic acid, picric acid, alcohol). Fixative mixtures show intermediate pictures. A particular picture is thus “created” by the different fixatives but a general orientation of the fibrils or of the network of the cell is always respected. This orientation can be conditioned by purely mechanical forces such as surface tension, intraprotoplasmic streams during the spreading of the cell but other factors play a role. It appears certain that there is a definite specificity in the cytoplasmic ultrastructure of the different kinds of blood cells studied and one can imagine that many other kinds of cells have also their own architecture. The electron microscopic studies do not appear to confirm in its totality Frey-Wyssling's “Haftpunkt-Theorie” but it remains a useful work-hypothesis if not, too schematically interpreted: the cytoplasmic ultrastructure shows a very great variety of dimensions and orientations specific for some cellular strains.