The cell in development and inheritance / by Edmund B. Wilson.

  • Edmund Beecher Wilson
Date:
1902, ©1900
Catalogue details

Licence: Public Domain Mark

Credit: The cell in development and inheritance / by Edmund B. Wilson. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    subject can best be considered after an account of that body. It may be mentioned here, however, that a large number of observers have maintained a giving off of nuclear substance to the cytoplasm, in the form of actual buds from the nucleus (Blochmann, Scharff, Balbiani, etc.) as separate chromatin-rods or portions of the chromatin network (Fol, Blochmann, Van Bambeke, Erlanger, Mertens, Calkins, Nemec, etc.) or as nucleolar substance (Leydig, Balbiani, Will, Ley- dig, Henneguy), but nearly all of these cases demand reexamination. B C Fig. 79. — Young ovarian eggs of birds and mammals. [Mertens.] A. Egg of young magpie (eight days), surrounded by the follicle and containing germinal vesicle and attraction-sphere. B. Primordial egg (oogonium) of new-born cat, dividing. C. Egg of new-born cat containing attraction-sphere {s) and centrosome. D. Of young thrush sur- rounded by follicle and containing besides the nucleus an attraction-sphere and centrosome (j), and a yolk-nucleus (j.;/.). E. Of young chick containing nucleus, attraction-sphere, and fatty deutoplasm-spheres (black). F. Egg of new-born cliild, surrounded by follicle and containing nucleus and attraction-sphere. (^) Yolk-nuclcns. —The term yolk-iiuclcus or vitelline body {Dottcr- kern, corps vitclliti) has been applied to various bodies or masses that appear in the cytoplasm of the growing ovarian Q.gg; and it must be said that the word has at present no well-defined mean- ing. As originally described by von Wittich ('45) in the eggs of spiders, and later by Balbiani ('93) in those of certain myriapods, the yolk-nucleus has the form of a single well-defined spheroidal