. The cell in development and inheritance. Cells. DIRECT OK AMITOTIC DIVI SI OX 115 sion of its total mass, but not of its individual elements or chromatin- granules (Fig. 56). Before the discovery of mitosis, nuclear division was generally assumed to take place in accordance with Remak's scheme (p. 63). The rapid extension of our knowledge of mitotic division between the years 1875 and 1885 showed, however, that such a mode of division was, to say the least, of rare occurrence, and led to doubts as to whether it ever actually took place as a normal process. As soon, however, as attention was
. The cell in development and inheritance. Cells. DIRECT OK AMITOTIC DIVI SI OX 115 sion of its total mass, but not of its individual elements or chromatin- granules (Fig. 56). Before the discovery of mitosis, nuclear division was generally assumed to take place in accordance with Remak's scheme (p. 63). The rapid extension of our knowledge of mitotic division between the years 1875 and 1885 showed, however, that such a mode of division was, to say the least, of rare occurrence, and led to doubts as to whether it ever actually took place as a normal process. As soon, however, as attention was especially directed to the subject, many cases of amitotic division were accurately determined, though. Fig. 56.â Group of cells with amitotically dividing nuclei; ovarian follicular epithelium of the cockroach. [WHEELER.] very few of them conformed precisely to Remak's scheme. One such case is that described by Carnoy in the follicle-cells of the it^^ in the mole-cricket, where division begins in the fission of the nucleolus, followed by that of the nucleus. Similar cases have been since described, by Hoyer ('90) in the intestinal epithelium of the nematode Rhabdoncnia, by Korschelt in the intestine of the annelid OphryotrocJia, and in a few other cases. In many cases, how- ever, no prehminary fission of the nucleolus occurs ; and Remak's scheme must, therefore, be regarded as one of the rarest forms of cell-division (!). ~ ~ 2. Centrosonie and Attractioii-spJierc in Amitosis The behaviour of the centrosome in amitosis forms an interesting question on account of its bearing on the mechanics of cell-division. Flemming observed (â 91) that the nucleus of leucocytes might in some cases divide directly without. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Wilson, Edmund B. (Edmund Beecher), 1856-1939. New
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectcells, bookyear1911
