246 Dr. A. Braun on the Vegetable Individual. 



fibres, which compose the cell-membrane according to the old 

 view advanced by Grew and lately revived by Meyen* and 

 J. Agardh f- These parts, it is true, have often been regarded 

 as the elementary forms % of plants, or their primary " indivi- 

 dualized " bodies § ; the attempts, however, to represent them as 

 the true and real vegetable individuals are not numerous ; and 

 they astonish us by their daring rather than entice to imitation. 

 Turpin, who commenced by considering plants to be composed 

 of different kinds of individual cells, which he compared with 

 various lower plants (especially the Algfe-genera Protococcus and 

 Conferva), afterwards expanded his views, so as to regard the 

 cells themselves as individuals of a second rank ; while he consi- 

 dered the true primary individuals to be the granules of the cell- 

 contents, from which, in his opinion, the cell (cell-wall) is formed 

 by agglomeration ||. Mayer of Bonn, basing his theory upon 

 molecular motions, considers the smallest granules of the cell- 

 contents as individuals possessing animal life (biospheres), which 

 build up plants for their dwellings. " Like hamadiyads these 

 sensitive monads inhabit the secret halls of the bark-palaces we 



* Meven, Pflanzenphysiol. i. p. 45 ; answered by Mohl, in his Ver- 

 raischte Schriften, p. 314. 



t J. Agardh, De Cell. Veg. fibrilhs tenuissimis contexta (1852). Not- 

 withstanding the importance of the author's new investigations, they still 

 need a more searching examination, as some points directly contradict 

 well-ascei-tained facts, e. g. the dii-ect transition of the fibres from the 

 outer to the inner layers of the cell- wall. The whole theory of the forma- 

 tion of cells bv the unintemipted growth of fibres cannot be admitted in 

 ■new of the midoubted independence of the formation of the cell-wall from 

 the contents. Mohl is certainly right in regarding the fibrous division 

 and divisibility of many cellular tissues as a mere structural relation of the 

 membrane (which in other parts is continuous) ; and he thinks it depends 

 upon the pecidiar mode of agglomeration of the molecules. As such mole- 

 cules of the cell-wall are invisible, I think it preferable to regard it as de- 

 pendent upon a regular change of the relations of density. 



X Kiitzing, Phil. Bot. i. p. 125, 12.9, does not regard the cell as the 

 elemental-}' form of ])lants, but as a complicated structure itself, and pre- 

 ceded by manv other more simple forms, which he comprehends under the 

 name of " molecular tissue," and which, he says, present in themselves 

 many lower vegetable forms ; — plants Avliich are not even cells ! 



§ Unger, Grundz. d. .\iiat. u. Phys. der Pflanzen, p. 4. The cell is re- 

 presented as the " elementary vegetable organ ;" but the vesicles, fibres 

 and granules within it are further distinguished as very minute, " indivi- 

 dualized " bodies. 



II Turpin, " Sur le nombre deux" (M^m. du Musee, xvi. 1827, p. 305) : 

 " Ainsi dos individus globulcux, rajiproches simplement contigus, forment 

 la membrane de la vesicule Individu du tissu cellulaire, le filament Individu 

 du tissu tigelhilaire, et la membrane cuticulaire Individu. l)cs agglome- 

 rations de ces derniers constituent les Individualites, provenantes des 

 bourgeons developpes, et enfin, celles-ci achevent V IndividuaUte composee 

 d'un arbre." 



