The elements of animal physiology / [William Alexander Osborne].

  • Osborne, W. A. (William Alexander), 1873-1967.
Date:
1909
Catalogue details

Licence: In copyright

Credit: The elements of animal physiology / [William Alexander Osborne]. Source: Wellcome Collection.

    13/160 (page 9)
    intricate mechanism rather than a simple substance, and it is in and around the nucleus that the greatest activities of the cell are manifest. Of the supreme importance of the nucleus many experiments give evidence. It has, for instance, been found possible in some of the larger single-celled creatures to tear off a portion of the protoplasm, and thus divide the cell into two parts, one with, and one without the nucleus. The unnucleated protoplasm continues to show some signs of life for a short time, but it has no power of repair or growth, and very soon dies. This is prettily shown with the Polystomella, a cell with a calcareous wall, which can be broken in the manner described. In the portion retaining the nucleus the • * 'AS?1 r •» • • • •••# ■v, •V>--2 Hr u • «* i M % I - 3 J V 1# » Ks 3. ^ —-■'o’**- \ * : t t ./ Pl.g‘ 2~/lustrations of the manifold variety in size and form of different bacteria. (After P. Baumgarten.) wound is speedily closed up with, a new shell, and the cell’s activities con- tinue unabated; the unnucleated portion, however, goes rapidly to pieces, and is eaten up by other micro-organisms. We may lay it down then, as an all-important law in physiology, that, if a cell be divided, that por- tion WHICH RETAINS THE NUCLEUS MAY LIVE, THAT PORTION WHICH IS CUT OFF FROM THE NUCLEUS MUST DIE. Fundamental Characters of Life. There are some characters common to all living things, both high and low, which may now be considered briefly: — iff'’ -RE^EWAL AND REPAIR.—It is essential to life that the different structures employed should be constantly renewed, not in large portions at a time, but each part in a gradual manner. We are familiar