Dr. A. Braun on the Vegetable Individual. 243 



as it is of sexual propagation*. The cell has a better right to 

 be considered as the vegetable individual than any other subor- 

 dinate member of the plant ; when connected with other cells it 

 still continues to be an independent sphere of formation, sharply 

 defined and, in youth at least, completely isolatedf. Before the 

 universal law of cell-formation was known, and before botanists 

 had succeeded in reducing all the elementaiy organs of plants 

 to cells, Tvu'pin hit upon the idea of seeking the vegetable indi- 

 vidual in the cell ; though his views did not rest on as solid a 

 foundation as Schleiden's assertion, that " in a scientific point 

 of view, the cell is the vegetable individual %.'* 



The most reliable authorities have agreed that new cells can 

 never be formed externally to, but only within, other cells already 

 formed §, so that cell-multiplication must be regarded as a pro- 

 pagation, while all the cells of the mature plant must be re- 

 garded as the progeny of the first embryonic cell. Besides, each 

 and every plant is at first a cell ; and there are single-celled plants 

 in the strictest sense of the term, in which the first formation of 

 new cells is that destined to reproduction ; i. e. the germinating 

 cells or spores II . Again, there are other plants in which the 

 cell-generations contained between the first generation (which 

 sprung from spores) and the last (itself returning into spores) 

 separate from each other, so that all the cells belonging to one 

 cycle of vegetable development are segregated, and live com- 



ilevelope into new plants, have long been known. The spores of the Cn'pto- 

 gamia belong here, as they aie cells originating and developing non- 

 sexually. 



* Pollen-cells, and the embryonic utricle and germinating cells, — as 

 well as those of the archegonium of the higher Cryptogamia. 



t Malpighi himself (Anatom. Plant. 1675) calls cells utriculi, or saeculi, 

 though he distinguishes the wood and bast-cells as '''■fibrcB," the vascular 

 cells as "Jistulce," and the cells containing milky saji as " vasa specialia." 

 As early as 1805, Link (Romer's Archiv, iii. p. 439) had expressed himself 

 very explicitly in regard to the isolated position and the independence of 

 cells : " Quaevis cellula sistit orgaiion peculiare, nullo hiatu nee poris con- 

 spicuis praeditum in vicina organa trauseuutibus. Conspicies nou raro cel- 

 lulam rubro colore tinctam inter reliquas virides." 



t Schleiden, Grundziige, Ite Aufl. 1842, vol. ii. p.4 [Eng. trans. (184!'), 

 p. 127 T.]. 



§ Cf. Schleiden, Grundziige, i. p. 267 [Eng. trans, p. 103 T.I : " 1 he 

 process of the propagation of cells, by the formation of new cells in their 

 interior, is a universal law in the vegetable kingdom." i\Iohl, Anat. und 

 Phys. d. veg. Zelle, 1851, p. 53 : "Cell-formation in plants takes place 

 only in the cavities of older cells, not between or upon them." Schacht, 

 Die Pflanzenzelle (1852), p. -17: "The formation of new vegetable cells 

 always takes place iu the interior of cells already formed." 



II E. g., Ascidium, C/njfridium, Corlinliam (a genus lately discovered ia 

 Heligoland), Sciadium. Hydrodicfyon (the last two with " colonial form- 

 ation "). 



