OF VEGETABLE TISSUE. 25 



of this deviation from the ordinary law of elas- 

 ticity, has been called cataleptic. The elastic 

 movements of plants are sometimes determined 

 byjan arrangement of the organs, which once 

 deranged, although spontaneously, have never- 

 theless no power to return to their original state ; 

 thus the four stamens of the parietaria tribes have 

 their filaments turned inwards before flowering ; 

 but as this process advances, and the filaments 

 enlarge, a moment arrives when they no longer 

 adhere together, but burst open with considerable 

 force : this is facilitated by the tubercles which 

 are formed in the inside of the filament ; the 

 anthers, shaken by this sudden movement, scatter 

 their pollen, the filaments die, and the phenome- 

 non can never be repeated. All these effects are 

 consequent on the manner in which the parts are 

 arranged, which indeed is connected with the life 

 of the plant, but must not be confounded with 

 those movements which are really dependent on 

 vital action. 



19. The power of imbibing moisture exists in 

 both organic and inorganic substances ; thus 

 deliquescent sails, as they are called, are so emi- 

 nently hygrometric, that their own particles are 

 in the end dissolved in the water they have im- 

 bibed. The effect cannot be carried to this extent 



