74 



solid matter, however minute, can under any 

 circumstances enter into the system of the plant. 



All the different organs of plants consist chiefly 

 of a series of sexagonal cells, separated from each 

 other by a thin membrane or cuticle. This cuticle 

 possesses a property, peculiar also to animal 

 membrane, which is called Endosmose, and by 

 which we understand a body that is permeable by 

 a liquid without being dissolved in it. 



If a pig's bladder containing a dense liquid say 

 syrup is suspended into a vessel containing pure 

 water, a peculiar interchange will take place 

 between the two liquids. Being of different 

 specific gravities, both will exert themselves to 

 bring about a balance of their respective densi- 

 ties ; the water will enter through the minute 

 pores of the bladder to dilute the syrup, and vice 

 versd the syrup will percolate into the pure water ; 

 and this interchange will continue until the density 

 of the two liquids is the same, or, in other words, 

 until an equilibrium between the lighter and 

 heavier liquid is established. It will, however, 

 invariably be found that the quantity percolating 

 into the denser liquid is far in excess of that which 

 percolates into the lighter liquid; and it would appear 

 that this wise law of nature has been expressly 

 framed to suit the requirements of vegetable life. For 

 if we consider now the rootlets of plants, consisting 

 of a number of these cells filled with a liquid 



