The first principles of heredity; with 75 illustrations and diagrms (1910) (14595438019)

Identifier: firstprincipleso00herb (find matches)
Title: The first principles of heredity; with 75 illustrations and diagrms
Year: 1910 (1910s)
Authors: Herbert, S. (Solomon), b. 1874
Subjects: Heredity
Publisher: London, A. and C. Black
Contributing Library: NCSU Libraries
Digitizing Sponsor: NCSU Libraries



Text Appearing Before Image:
a Fig. 20.—A Cell. (From H. W. Conn, Story of LifesMechanism.) protoplasmic network ; b, liquid inits meshes ; c, nuclear membrane ;d, nuclear network ; e, chromatinnet^vork ; /, nucleolus; g, centro-some; h, aster; i, vacuole or air-space ; /, inert bodies.
Text Appearing After Image:
Fig. 21.—Karyokinesis. (Adapted from E. B. Wilson.) (From Weismann, The Evolution Theory.) A, resting-phase ; B, chromatin (chr) in coiled thread; C, eightchromosomes (chrs) and two asters formed; D, chromosomessplit and lying in equatorial plane, the two centrosomes (csph)at the poles ; E, chromosomes separate ; F, division of cell-substance; G, final formation of two daughter-cells; zk, cell-substance ; kk, nucleolus ; km, membrane of nucleus ; aeq, equa-torial plane ; ksp, radiating fibres. 32 THE FIRST PRINCIPLES OF HEREDITY centrosome, destined to play an important part in theprocess of division. The first stage of the division is initiated by a rearrange-ment of the chromatin into a long thread, which imme-diately breaks up into a number of small pieces, called the Chromosomes. The number of these chromosomes isthe same for all ordinary cells of the organism, and doesnot vary within any given species. At the same time, thecentrosome, which lies just outside the nucleus, has di