. Physiological botany; I. Outlines of the histology of phænogamous plants. II. Vegetable physiology. Plant physiology; Plant anatomy. PROTOPLASM. 27 of the protoplasm,' as, for instance, a solution of common salt, the protoplasm separates from the cell-wall, and b^' its con- traction shows clearly that it is a closed sac. At a later stage in some cells even this thin protoplasmic sac wholly dis- appears. 121. Protoplasm Itself must be regarded as essentially transparent and colorless, but it is seldom found without some admixture of other mat- l^r^h ters, which give it a granul-ar appearance.
. Physiological botany; I. Outlines of the histology of phænogamous plants. II. Vegetable physiology. Plant physiology; Plant anatomy. PROTOPLASM. 27 of the protoplasm,' as, for instance, a solution of common salt, the protoplasm separates from the cell-wall, and b^' its con- traction shows clearly that it is a closed sac. At a later stage in some cells even this thin protoplasmic sac wholly dis- appears. 121. Protoplasm Itself must be regarded as essentially transparent and colorless, but it is seldom found without some admixture of other mat- l^r^h ters, which give it a granul-ar appearance. The granules are generallj" very small, and f '^_ as a rule are not found at the periphery of the mass. The limiting surface of the proto- plasmic mass is further dis- tinguished by being somewhat denser and firmer than the sub- stance it encloses ; and although it cannot be separated from the latter M'^ mechanical means, it is often spoken of as a film ['^. which take up the coloring matter readily, le;iving the remainder of the mass unstained. It is believed by Schmitz that the unstained mass is a homoge- neous liquid filling the meshes (Sitzungsber. der niederrhein. Gesellschaft in Bonn, 1880). 1 Such substances ai'e termed plasmolytic agents. 2 Of the appearance of-protoplasm, the following remarks by Mohl, who first gave it the name iu 1846, are of interest. " If a tissue composed of young cells be left some time in alcohol, or treated with nitric or muriatic acid, a very thin, finely granular membraue becomes detached from the inside of the wall of the cell in the form of a closed vesicle, which becomes more or less con- tracted, and consequently removes all the contents of the cell, which are enclosed in this vesicle, from the wall of the cell. Reasons hereafter to be discussed have led me to call this inner cell the primordial utricle. ... In the centre of the young cell, with rare exceptions, lies the so-called nucleus celltilce of Eobert Brown. . The remai
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