262 Examination of the Matured Frameivork [BOOK n. 



phenomena of vegetative life, that the true cell-body, the cell- 

 protoplasm is prior in time and in conception, and can claim 

 the higher position. 



Mirbel, to whom we now return, had in 1801 laid down a 

 theory of cell-formation which agreed in the main with that of 

 Caspar Friedrich Wolff; he supposed with Wolff that each 

 cell-space was separated from its neighbour by a single wall, 

 and relying on fresh observations asserted the existence of 

 visible pores in the dividing walls of parenchyma and of vessels, 

 and also maintained some new views on the nature and forma- 

 tion of vessels. The essential points of this theory found an 

 opponent in Germany in the person of KURT SPRENGEL, the 

 well-known historian of botany, and one of the most variously 

 accomplished botanists of his time, who had published in 1802 

 a work written in diffuse and familiar style under the title of 

 ' Anleitung zur Kenntniss der Gewachse.' He relied on his 

 own observations, but these were evidently made with small 

 magnifying powers, an obscure field of sight, and indifferent 

 preparations. The cell-tissue, says Sprengel, consists of cavities 

 of very various shape communicating with one another, the 

 dividing walls being in some places broken through and in 

 others wanting. He took the starch-granules which he saw in 

 the seed-leaves of beans and other plants for vesicles, which 

 increase in size by absorption of water and so form new tissue ; 

 but he did not explain how we are to conceive of the growth of 

 organs with such a mode of cell-formation. His account of the 

 vessels is extremely obscure, even more obscure than Hedwig's, 

 though he has the merit of refuting the latter's strange theory 

 of reconducting vessels in the epidermis ; he also suggested, 

 though only incidentally, the happy idea that spiral passages and 

 even vessels might arise from cell-tissue, since the youngest 

 parts of plants have only the latter ; but he did not attempt to 

 explain how or where the process takes place. Like Malpighi 



