Remarks on Quekett's Histology, On Kölliker's Human histology, and on the physiological importance of the nucleus of the cell / by Martin Barry, M.D.

  • Barry, M. (Martin), 1802-1855.
Date:
[1854]
Catalogue details

Licence: Public Domain Mark

Credit: Remarks on Quekett's Histology, On Kölliker's Human histology, and on the physiological importance of the nucleus of the cell / by Martin Barry, M.D. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    development of the ovum, furnish remarkable examples of the for- mation and reproduction of cells ivithin a nucleus. Farther, the true cleavage of the yelk-ball in certain animals, admits of comparison with the cleavage of other nuclei. C'eZ^division, I repeat, is an unfortunate expression, it being only nuclei that are cleft. Yet there is but one kind of reproduc- tion, viz., the fissiparous. For, though the membrane of the cell undergoes no actual cleavage, a mother cell does not reproduce without cleavage of its nucleus.^ Kolliker seems altogether to deny true cleavage in the ovum. Instead of cleavage, he supposes his primaxy nucleus, the pellucid centre of the yelk-ball, to operate as a centre of attraction upon the yelk and unite into a globular mass, the first cleavage mass ; and he thinks that then the nucleus becomes resolved into two halves, these acting as new centres upon the yelk, and thus breaking up the first cleavage mass into two. Each of these has its nucleus, which also becomes resolved into two halves. These in their turn acting as centres of attraction, double the number of yelk masses, thus increased to four, and so on. The editors of Kolliker altogether demur to the notion that the ' nuclei' of the dividing yelk exercise any attraction upon the yelk substance, and for demonstrative evidence that no such attraction exists, they refer to the observa- tions of Reichert,^ of Remak,'' and of Nelson.* It appears to me far from improbable that in the ova which Kol- liker has particularly investigated, there may take place no true cleavage. But with his editors I altogether demur to the notion of attraction in its stead. I venture to believe that what Kolliker had before him and referred to atti-action, was no other than the very process I described in the mainmiferous ovum. Thus the small globules of Kolliker are the product of my transitory cells. And his new nucleus, the primary nucleus of the embryo, is what I maintain to result in mammalia from the fecundated centre of the germ spot. As to membranes being formed around the cleavage masses, by which the latter become actual cells, as supposed by Kolliker, this is certainly a mistake. The veiy title of a paper by Reichert, mentioned by the editor's when demurring to Kolliker's notion of attraction, shows that he denies the formation of a cell around the cleavage masses.' And as to a new nucleus arising around a new Ttucleolus, nothing of the kind takes place in the mam- miferous ovum, nor anywhere else. Farther, for a refutation of Kolliker's idea, that the investing globules developed by the suc- cessive multiplication of nuclei, become cells only in the latest ^ See a Paper of mine, On fissiparous generation. Edinburgh New Phil. Journal, Oct. 1843. 2 Miiiler's Arcliiv., 1846. » MUller's Archiv., 1851. ♦ Piiil. Trans., 1862. ' The title of Reichert's paper is: Der Furchungs-Prozess und die logenannte, [so-called] Zellenbildung um Inhalts-portionen.