Elements of histology / by E. Klein.

  • Klein E. (Edward), 1844-1925.
Date:
1883
Catalogue details

Licence: Public Domain Mark

Credit: Elements of histology / by E. Klein. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    terstitial substance of the nuclear matter—^.e., the pale substance contained in the original reticulum of the nucleus. Flemming calls this substance achromatm, whereas the threads forming the original network, the convolution, aster and diaster, he calls chromatin, on account of its readily staining with dyes. In this stage the whole figure resembles a spindle, the nuclear spindle of Biitschli (Fig. 5, f). (/) Further, all connection between the two sets of threads is broken—i.e., between the stars of the diaster. (g) The threads of each set become greatly convoluted. (A) A membrane appears for each set. In this stage we speak of two new or daughter nuclei. The cell protoplasm may commence to divide at any stage between the one wlien the threads aggregate round two centres, and the one when two distinct daughter nuclei are present; or the division of the nucleus may not be followed by the division of the cell protoplasm, in which case we have a two-nucleated cell. In some instances, especially of invertebrates and lower vertebrates, a peculiar sun-like arrangement of fibrils of the cell protoplasm towards each of the two stars of the above nuclear fibrils has been observed. Martin has noticed, in pathological new growths, a simultaneous division into three and four daughter nuclei, after the mode of karyokinesis. Although this indirect mode of division of the nucleus has been observed in all kinds of cells in the embryo, and to a limited degree also in the adult, it is not proved to be the universal mode of nuclear division. On the contrary, there is strong evidence that in amoeboid corpuscles division of the nucleus follows the direct mode, and it is also probable that other nuclei, under certain conditions, may undergo the direct mode of division.
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