Text-book of botany, morphological and physical / by Julius Sachs ; edited, with an appendix, by Sydney H. Vines.

  • Sachs, Julius, 1832-1897.
Date:
1882
Catalogue details

Licence: Public Domain Mark

Credit: Text-book of botany, morphological and physical / by Julius Sachs ; edited, with an appendix, by Sydney H. Vines. Source: Wellcome Collection.

    18/1000 (page 2)
    consisting of a peculiar substance, which we call Cellulose (Fig. B, C, h). Close to the inner side of this membrane, which forms a closed envelope, is a second layer, also entirely continuous, the substance of which is soft and inelastic, and which always contains albuminous matter; to this substance H. v. Mohl gave the distinctive appellation of ProtoplasmIn the cells now under consideration it forms a sac enclosed by the cell-wall, in which sac other portions of protoplasm are also usually present in the form of plates and threads (Fig. I, B, C, p). Absent from some of the lowest or- ganisms, but present in all the higher plants without excep- tion, there lies imbedded in the protoplasm a roundish body, the substance of which is very similar to that of the protoplasm, the Nucleus {A, C, k). The cavity enclosed by the protoplasm-sac is filled with a watery fluid, the Cell- sap {B, C, s). In addition to these, there are also very com- monly found in the interior of the cell granular bodies, which however may be passed over for the present. Cells, in the stage of deve- lopment now described, consist therefore of a firm membrane, semi-solid protoplasm (includ- ing the nucleus), and fluid cell- sap. At first, however, the cell- sap is wanting. If the same cells are examined in a very early stage of their development they are smaller {A), their cell-wall thinner, and the protoplasm forms a continuous mass, in the middle of which lies the nucleus, at FIG. I.—P.irenchymatous cells from the ntedian cortical layer of the root of Fritillaria itnperialis; longitudinal sections (x 550). A very young cells lying close to the apex of the root, still without cell-sap. B cells of the same description about 2 mm. from the apex of the root, the cell-sap s forming separate drops in the protoplasm/; between the drops are plates of protoplasm; C cells of the same description about 7—8 mm. from the apex of the root; the two cells to the right below are seen in a front view ; the large cell to the left below is in optical section; the cell to the right above is opened by the section; the nucleus shows, under the influence of the penetrating water, a peculiar appearance of swelling {x, >). ' H. V. Mohl, Ueher die Saftbewegungeii im Inneren der Zellen, Bot. Zeitg. 1846, p. 7.^. The importance of this substance to the life of the cell was recognised at the same time by Nageli, who, in conjunction with Schleiden, termed it ‘Schleim.’ (Zeitschr. für wissensch. Bot. von Schleiden u. Nägeli, Heft III, 1846, p. 5.^) [The ‘nucleus’ was figured by F. Bauer in 1830 in the stigmatic cells of liletia Tankervillice from a sketch made in 1802. Meyen in the former year indicated it in his ‘ Phytotomie.’ It was first described by Robert Brown (see Misc. Bot. Works, vol. I. p. 512) in 1833. Schwann in 1839 applied the term ‘nucleolus’ to the body previously discovered by Schleiden (Schwann and Schleiden’s Researches, p. 3). Cohn in 1850 pointed out the analogy of the ‘ protoplasm ’ cf botanists with the ‘ sarcode ’ of zoologists.]