. A Manual of botany : being an introduction to the study of the structure, physiology, and classification of plants . Botany. MOVEMENTS IN CELLS — ROTATION. 151 experiments that the sap raised the mercury upwards of thirty inches. The apparatus used by Hales is similar to that used by Dutrochet, to measure endosmose, as is represented at fig. 243, where c is the stem of a i vine cut, t is a bent glass tube fitted to the cut extremity of the vine by a copper ring, v, carefully luted and secured by a bit of bladder, m; n n, represents the level of the mercury in the two branches of the lower cu
. A Manual of botany : being an introduction to the study of the structure, physiology, and classification of plants . Botany. MOVEMENTS IN CELLS — ROTATION. 151 experiments that the sap raised the mercury upwards of thirty inches. The apparatus used by Hales is similar to that used by Dutrochet, to measure endosmose, as is represented at fig. 243, where c is the stem of a i vine cut, t is a bent glass tube fitted to the cut extremity of the vine by a copper ring, v, carefully luted and secured by a bit of bladder, m; n n, represents the level of the mercury in the two branches of the lower curvature, before the experiment, and n' n' the level at the conclusion of it. He calculated that the force of the sap in the vine, in some of his experi- ments, was five times greater than that of the blood in the crural artery of the horse. Special Movements of Fluids. —Besides this general circulation of the sap, special movements have been observed in the individual cells of plants, which have been included under the name of Rotation (rota, a wheel) or Gyration (gyrus, a circuit or circle). These motions have been de- tected in the cells of many aquatic plants, especially species of Ohara and Vallisneria, and in the hairs of Trades- cantia. The currents proceed in a more or less spiral direction, and are rendered visible by the granules of chlorophyll which they carry along with them. There exist also other granules in the fluids, whiph are coloured yelloy by iodine, and are probably of a nitrogenous nature. The species of Chara (fig. 244) in which rotation has been observed, are aquatic plants growing in stagnant ponds, and composed of a series of cylin- drical cells, placed end to end. Some- Fig. 243. Apparatus of Hales, to show the force of ascent of the sap. c, Stem of a vine cut. ty A glass tube with a double curvature attached to the upper pai-t of the vine-stem, by means of a copper cap, v, which is secured by means of a lute and piece of bladder, m. n n, Level of
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