. The cell in development and inheritance. Cells. 312 SOME PROBLEMS OF CELL-ORGANIZATION cotte, Van der Stricht, Meves, and others apply the term to the central granule or granules plus the surrounding sphere (" centrosome" of Boveri), which they regard as equivalent to the medullary zone of Van Beneden, the " corpuscule central" of the last-named author being identified with the central granule or "centriole" of Boveri, though the latter structure is considerably smaller than the former as described by Van Beneden. The matter of fact turns largely on the question
. The cell in development and inheritance. Cells. 312 SOME PROBLEMS OF CELL-ORGANIZATION cotte, Van der Stricht, Meves, and others apply the term to the central granule or granules plus the surrounding sphere (" centrosome" of Boveri), which they regard as equivalent to the medullary zone of Van Beneden, the " corpuscule central" of the last-named author being identified with the central granule or "centriole" of Boveri, though the latter structure is considerably smaller than the former as described by Van Beneden. The matter of fact turns largely on the question whether the astral rays traverse the larger sphere to the central granule. That such is the case in Ascaris is positively asserted by Kostanecki and Siedlecki, ('97) and as positively denied by Fiirst ('98) with whose observations. Fig. 153. — Structure of the centrosome in the polar asters of a gasteropod, Diaulula. [Mao FARLAND.] A. Mitotic figure, formation of first polar body. B. Inner aster at final anaphase; central granule double within the " ; C. Elongation of old " centrosome " to form second polar spindle. those of MacFarland ('97) on gasteropod-eggs agree. On the other hand, in the turbellarians the observations of Francotte ('97, '98) and Van der Stricht ('98, i) seem to leave no doubt that the larger sphere ("centrosome"), here very sharply defined and staining deeply in iron-haematoxylin, is traversed by well-defined astral rays converging to the central corpuscle, and both these observers agree further that botJi the corpiiscle and the sphere divide to persist as the "centrosomes'^ of the daughter-cells — a result in conformity with Van Beneden's con- clusion in the case of Ascaris. Lillie's valuable observations on the polar asters of Unio ('98) afford, I believe, conclusive evidence as to the nature of the sphere. In the. Please note that these images are extracted from scanned page images that may have been di
Size: 2019px × 1238px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectcells, bookyear1911
