. The cell in development and inheritance. Cells; Cells. 24 GENERAL SKETCH OF THE CELL. nuclear substance par excellence, is known as chromatin (Flemming) on account of its very marked staining capacity when treated with various dyes. In some cases the chromatin forms a nearly continu- ous network, but it often appears in the form of more or less detached rounded granules or irregular bodies. The second constituent is a transparent substance, invisible until after treatment by reagents, known as li)iin (Schwarz). This substance, which is probably of the same nature as the cyto- plasmic network
. The cell in development and inheritance. Cells; Cells. 24 GENERAL SKETCH OF THE CELL. nuclear substance par excellence, is known as chromatin (Flemming) on account of its very marked staining capacity when treated with various dyes. In some cases the chromatin forms a nearly continu- ous network, but it often appears in the form of more or less detached rounded granules or irregular bodies. The second constituent is a transparent substance, invisible until after treatment by reagents, known as li)iin (Schwarz). This substance, which is probably of the same nature as the cyto- plasmic network outside the nucleus, surrounds and supports the chromatin, and thus forms the basis of the nuclear net- work. c. The nucleoli, one or more larger rounded or irregular bodies, suspended in the net- work, and staining intensely with many dyes ; they may be absent. The bodies known by this name are of at least two different kinds. The first of these, the so-called true nucleoli or plasmosomes (Figs. 5, 7, B, 10), are of spherical form, and by treatment with differential stains such as haematoxylin and eosin are found to consist typi- cally of a central mass staining like the cytoplasm, surrounded by a shell which stains like chromatin. Those of the other form, the "net-knots" (Netz- knoten), or karyosovies, are either spherical or irregular in form, stain like the chromatin, and appear to be no more than thickened portions of the chromatic network (Figs. 5, 7, A, 10). Besides the nucleoli the nucleus may in exceptional cases contain the centrosome (p. 225), which has undoubtedly been confounded in some instances with a true nucleolus or plasmosome.^ There is strong evidence that the true nucleoli are 1 Flemming first called attention to the chemical difference between the true nucleoli and the chromatic reticulum ('82, pp. 138, 163) in animal cells, and Zacharias soon afterwards studied more closely the difference of staining-reaction in plant-cells, showing that the. P
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectcells, bookyear1896
