APPENDAGES OP THE AXOPHYTE. 35 



der ; partly fill the tube with a strong solution of sugar, and 

 immerse it in a vessel containing water. In an hour, or more, 

 the denser fluid will be found to have attracted the water 

 through the membrane and to have risen considerably in the 

 tube. This property is called Endosmosis, {evSav, inwards, jkom, 

 I seek.) 



Fig. 9. 



n 



Now the cells of the roots and the entire system of the 

 plant, owing to the evaporation of water from the leaves, always 

 contain a fluid dense and concentrated. The water in the 

 earth is therefore attracted into the plant by means of the 

 denser fluid contained in the cells of the root, — or in other 

 words, it' enters the plant by endosmosis. 



This simple endosmotic law pervades all vitally active and 

 newly formed vegetable tissues, and seems to be the only cause 

 of all the remarkable movements of roots. For example, it is 

 well known that roots will turn aside from a barren for a 

 fertile soil, so that to stop their growth in any given direction, 



