II. THE continued investigations into the structure of cells, both in plants and animals, led to modifications in the conception of their morphology. Hugo von Mohl announced that he had discovered (Botanische Z'eitung, translated by A. Henfrey in Taylor's “Scientific Memoirs,” vol. iv., 1846) in the vegetable cell, after being acted on by alcohol and iodine, a thin nitrogenous membrane distinct from and applied to the inner surface of the cellulose wall of the cell, which he named the primordial utricle. He regarded it as forming a vesicle within the cell wall, and containing the contents and the nucleus. By subsequent observers it has been shown that the primordial utricle is nothing more than a thin layer of protoplasm lying close to the cellulose wall, and inclosing the sap cavity of the cell.
"On the Physical Basis of Life," a Lay Sermon delivered November 8 1868, Fortnightly Review; also in "Lay Sermons and Addresses," London., 1870.
Dr. J. M. Macfarlane has described as constantly present within the nucleolus of vegetable cells a minute body, which he terms nucleolo-nucleus or endonucleolus. He considers it, as well as the nucleolus, to become constrict ed and divided before the nucleus and the cell pass from the resting into the active phase of cell multiplication. See Trans. Bot. Soc. Edin., 1880, vol. xiv., and Trans. Roy. Soc. Edin., 1881–82, vol. xxx.
"Lectures on the Physiology of Plants," by Julius von Sachs ; translated by H. Marshall Ward, Oxford, 1887.