THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[THIRD SERIES.] 

 No. 76. APRIL 1864. 



XXVII. — Histological Researches on the Formation, Development, 

 and Structure of the Vegetable Cell. By Prof. H. Karsten*. 



[Plates v., VI., VII.] 



Historical Introduction. 



Since the period when Malpighi, Grew, and Leeuwenhoek laid 

 the foundations of vegetable anatomy, and Moldenhauer, Mirbel, 

 Bernhardi, Treviranus, Rudolphi, Link, Meyen, Unger, Dumor- 

 tier, Mohl, and others demonstrated the tissue of plants to be 

 composed of distinct independent cells, the history of the deve- 

 lopment of the cell itself has formed an object of inquiry. As 

 yet, however, the researches made on this question have led to 

 no uniform and constant conclusions, as, indeed, from the very 

 nature of the inquiry, might have been anticipated. 



On the one hand, Mohl, in 1835, maintained the hypothesis 

 of the multiplication of cells by fission of pre-existing cells, 

 effected by means of septa commencing as folds from the sides 

 of the cells and advancing until they met in the centre. On 

 the other hand, Schleiden seized on the fact of the frequent 

 presence of a nucleus, which Robert Brown had pointed out in 

 cells where an active process of development was going forward, 

 and employed it to construct a contrary doctrme of cell-pro- 

 duction. 



Schleiden regarded this nucleus as the basis and builder of 

 the simple cell-wall that encloses it, by effecting a transforma- 

 tion of the mucilaginous substance around it into a gelatinous 

 envelope, which subsequently becomes the membranous wall. 

 Into the gelatinous vesicle so formed Schleiden supposed the 

 external fluid to pass on one side, and to distend it, so that the 

 mucous corpuscle is set free on one side, but adheres to the inner 

 wall on the other — and that then a second layer is produced on 



* Translated by Dr. Arlidge from a separate impression kindly commu- 

 nicated by the Author. 



Ann. ^ Mag. N. Hist. Ser. 3. Vol. xiii. 18 



