Atlas and epitome of human histology and microscopic anatomy / by Johannes Sobotta ; edited, with extensive additions, by G. Carl Huber.

  • Sobotta Johannes, 1869-1945.
Date:
1903
Catalogue details

Licence: In copyright

Credit: Atlas and epitome of human histology and microscopic anatomy / by Johannes Sobotta ; edited, with extensive additions, by G. Carl Huber. 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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    iiizecl between tliem; this enlarges as the eentrosomes con- tinue to move apart. Tliis is tlie anlage of the so-called central .'<pimUe or the uniting tilainents, a portion of the achromatic s])iiulle, which forms an e.ssential })ortion of the fioure of mitotic cell division. There are further de- veloped rays, which pass out from the eentrosomes in opposite directions toward the j)eriphery of the cell; these are known as polar rays. The origin of this achro- matic spindle is not as yet fully established. It woidd seem prol)al)le, however, that the liuin network of the nucleus contrihutes to the formation of the .structure. While the spindle, the poles of which arc formed bv the centnjsome.s, is .still further inereasing in size, the chromo.somes arrange themselves about the equator of the spindle in nearly one plane, the equatorial plate. This stage is designated as that of the mother star, or monaster. The dividing cell is now (‘asily distinguished from the resting cell. In ])lace of the nueleiis a clear area is found, in which may be observed the mother star, or monaster, so named bceau.'^e, whcai viewed from one pole, the ehromosomes form a star-like figure. Besides the fibers of the central s])indle, another system of fibers develo])s—that of the traction jihern or mantle filaments. The.se are generally finer than those of the cential spindle and are present in gr(‘ater numbers. They run from the eentrosomes to the ehromosomes and attach tluanselves to each of the latter in such a manner that the fila'rs (doming from one centi'osoine insert themselvc's into the adjacent half of the looj). In the mechanism of mitosis the.se fibers are believed to play a part in the processes of metakinesis which now follow ; th(>y draw apart the halves of the loops tf)ward the o|)posite poles of the spindle. Mcta- kine.FiH beirins when, in th(! e(|iiatorial |)late, the longi- tudinal cleavage of the ehromosoiiK's is v(>rv distiiietlv si'Cii ; the interspace between two daiightei- eliromosomes becomes gradually greater, a change* in the whole mitotie^ figure going hand in hand with this [erocess. A double