. The cell in development and inheritance. Cells; Cells. with the division of the nucleohis, is continued by simple constriction and division of the nucleus, and is completed by division of the cell- body and membrane (Fig. i8). For many years this account was accepted, and no essential advance beyond Remak's scheme was made for nearly twenty years. A number of isolated observations were, however, from time to time made, even at a very early period, which seemed to show that cell-division was by no means so sim- ple an operation as Remak believed. In some cases the nucleus seemed to disappear
. The cell in development and inheritance. Cells; Cells. with the division of the nucleohis, is continued by simple constriction and division of the nucleus, and is completed by division of the cell- body and membrane (Fig. i8). For many years this account was accepted, and no essential advance beyond Remak's scheme was made for nearly twenty years. A number of isolated observations were, however, from time to time made, even at a very early period, which seemed to show that cell-division was by no means so sim- ple an operation as Remak believed. In some cases the nucleus seemed to disappear entirely before cell-division (the germinal vesicle of the ovum, according to Reichert, Von Baer, Robin, etc.); in others to become lobed or star-shaped, as described by Virchow and by Remak himself (Fig. i8,/). It was not until 1873 that the way was opened for a better understanding of the matter. In this year the discoveries of Anton Schneider, quickly followed by others in the same direction by Biitschli, Fol, Strasburger, Van Beneden, Flemming, and Hertwig, showed cell-division to be a far more elaborate process than had been supposed, and to involve a com- plicated transformation of the nucleus to which Schleicher ('78) afterwards gave the name of Karyokinesis. It soon ap- peared, however, that this mode of division was • not of univer- sal occurrence ; and that cell- division is of two widely different types, which Van Beneden {^7^) distinguished as fragnientatioit, corresponding nearly to the simple process described by Remak, and division, involving the more com- plicated process of karyokinesis. Three years later Flemming ('79) proposed to substitute for these the terms direct and indirect division, which are still used. Still later ('82) the same author suggested the terms mitosis (indirect or karyokinetic division) and amitosis (direct or akinetic division), which have rapidly made their way into general use, though the earlier terms are often employed. Modern rese
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectcells, bookyear1896
