SECT. I. ELEMENTARY ORGAN'S. 201 



longitudinal fibres giving tenacity to the whole. 

 These parts have been developed no doubt by means Formed 



r . . , i ' out of th 



of the agency of the vital principle operating on p r0 pe r 

 the proper juice ; but what have been the several Juice ' 

 steps of operation ? 



Some phytologists have attempted to account for Which 

 the formation of the above parts by supposing the SU pp sed 

 proper juice to consist of multitudes of organic 

 fibres, which being united together by the vege- fibres - 

 table gluten constitute the cellular and tubular 

 tissue, and thus form the mass of the plant. But this 

 supposition leaves us just where we were before, 

 For if it were even proved to be the fact, the next 

 question would be, how are the organic fibres 

 themselves formed ? But as it is an assumption 

 founded on no proof, it merits of course no fur- 

 ther consideration. Perhaps no satisfactory expli- 

 cation of the phenomenon has yet been offered, 

 though M. Mirbel, in the want of all plausible con* 

 jecture, submits the following: He supposes the Or to b 

 proper juice to be at first converted into a fine mem- b"e 

 brane, which he calls the membranous tissue, from 

 which the cellular tissue of the pulp is afterwards sue 

 formed, by means of the foldings and doublings of 

 the original membrane, so as to present an hexa- 

 gonal appearance similar to that of the cells of the 

 Bee. The tubular tissue he supposes to be in like From 

 manner formed out of the cellular tissue, by means 

 of such openings and perforations as may be acci- 

 dentally effected in the tissue itself, from the 



"lnto" 



