. Principles of the anatomy and physiology of the vegetable cell. Plant cells and tissues. THE VEGETABLE CELL. 41 ters (usually red or blue) are dissolved in it; and still more rarely is the quantity of the xincoloured substances, such as gum, dissolved in it, so great as to increase in a striking manner its power of refracting light. In many, yet comparatively rare, cases, the cell-sap of particular cells becomes wholly displaced by compounds -which the cell itself prepares, e. g., etherial oils. Ohser'o. Among the organs of the higher plants, ripe seeds alone bear to be perfectly dried witho
. Principles of the anatomy and physiology of the vegetable cell. Plant cells and tissues. THE VEGETABLE CELL. 41 ters (usually red or blue) are dissolved in it; and still more rarely is the quantity of the xincoloured substances, such as gum, dissolved in it, so great as to increase in a striking manner its power of refracting light. In many, yet comparatively rare, cases, the cell-sap of particular cells becomes wholly displaced by compounds -which the cell itself prepares, e. g., etherial oils. Ohser'o. Among the organs of the higher plants, ripe seeds alone bear to be perfectly dried without being killed; the older wood of trees may also lose a great quantity of its sap without death ; the limit to which this is possible is as yet unknown. The rest of the organs, particularly the leaves, do not bear any considei^able loss of water. It is diiforent in many lower plants, especially the Mosses, Lichens, and many Algse, e, g., m Nostoc^ which may be completely dried up without injury. c. Granular structures. In the majority of parenchymatous cells, organic structures— usually of granular form—are met with, at all events at certain periods of the life, swimming in the cell-sap or slightly adherent to the walls. Two of these, the chlorophyll granules and starch are very generally diffused. (JkloTopliyll (leaf-green), on the presence of which ^'^9- ^5. depends the green colour of plants, never occurs dissolved in the sap, but always in the form of a softish mass of definite or indefinite shape ; many phytotomists have asserted the existence of a green- coloured cell-sap, but I have never been able to nncl iu4 Amorphous clilorophyll forming patches or tlnreads which adheres to the cell-wall and the granules con- tained in the cell, is of comparatively rare occur- rence, yet it occurs here and there in the Phane- rogamia, in the same cells with the chlorophyll granules. Usually chlorophyll possesses a sharply defined form. In certain Algse it presents itself in the f
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectplantcellsandtissues
