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REVIEWS. 



Unteksuchungen ubek den Bau und die Bii-dukg dek Pflakzek- 

 ZELLE. Von Dr. H. Pringsheim, &c. GruiKllinien eiuen Theorie der 

 Pflanzenzelle. Mit. 4. Colorirt. Tafeln. Berlin, 1854. 



Researches ox the Structure axd Formation of the Vegetable 

 Cell. By Dr. H. Pringsheim. (Notice from ' Bot. Zeituno;,' Maj-, 

 1855.) 



This memoir, which constitutes the first part of researches 

 respecting the vegetable-cell, is dedicated to the author's 

 friend, Dr. F. Cohn. Its object is to afford a new doctrine 

 and new views with respect to the primordial utricle, differing 

 from those at present entertained. The avithor first proceeds 

 to give an account of the primordial utricle, in accordance 

 with which the principal part in the life of the cell is 

 ascribed to that element which has been regarded as the 

 essential, often the onlv completely closed, nitrogenous mem- 

 brane of the plant-cell, and upon this subject the statements 

 of some observers are communicated. A second section treats 

 of the disposition of the contents of the vegetable-cell ; these 

 contents consist of the proper cell-fluid, which is always 

 found in the interior, and of the external, peripheral, sur- 

 rounding protoplasma (or more shortly, plasma), in which the 

 granular portions of the cell-contents are always imbedded. 

 A distinct lamination is apparent in this plasma, that is to 

 say, it is constituted of an external, colourless layer applied to 

 the cell-wall, and which never presents any granules, and 

 termed by the author " the cutaneous layer," and of an in- 

 ternal, frequently of a dense mucoid consistence and granular 

 aspect, " the granular layer" of the author. When this granular 

 layer is of some thickness the chlorophyll granules will be 

 found lying in its outer portion, whilst the inner part will be 

 seen to consist merely of a colourless, muco-granular sub- 

 stance, in which, it is true, many kinds of colourless, coarse, 

 granular particles occur, but never chlorophyll-granules or 

 amorphous chlorophyll. The parietal cytoblast is invariably 

 lodged in the " granular layer," and when this layer consists 

 of two portions it is always found in the inner one. In cases 

 where movement is observed in the cell, it always takes place 

 at the boundary between the ''granular layer" and the cell- 

 fluid. When the granular layer is thin, the whole of it 

 moves together with the chlorophyll granules imbedded in it, 

 but when it is divided into two portions, the movement in- 



