VEGETABLE LIFE. '21 



either is too dry, the leaves and shoots become 

 flaccid and droop from their natural position ; but 

 when humid air or water is restored to the plant, the 

 flaccid parts recover their rigidity and position : such 

 movements are easily accounted for. Other motions 

 are produced by the action of heat and light, which 

 have the effect of expanding flowers and foliage ; but, 

 being withdrawn, they relapse to a state of repose, 

 which is called their sleep. The pedicels of some 

 flowers, as Convolvulus, are erect or horizontal while 

 in bloom, but immediately turn downward to ripen 

 the seed. Extraordinary motions are those of the 

 pinnulse of Desmodium gyrans * ; the collapsing of 

 the leaflets of Dioncea^, and Mimosa I, the elastic 

 action of the stamens of Berberis^ and that of the 

 petals of some of the Orchidece || . All these spon- 

 taneous motions are wonderful ; and cannot be ratio- 

 nally accounted for from any knowledge we possess 

 of the articulations which become so suddenly and 

 alternately lax and rigid. 



These instances sufficiently prove that plants are 

 sensitive and irritable ; whence some philosophers 

 have come to the conclusion, that they are actually 

 endowed with muscles, a system of nerves, and not 

 only recede from the contact of animals, but, more- 

 over, are conscious of pleasure and pain ! It is certain 

 that the appearance of a healthy plant soon after the 

 morning sun shines upon it, and while " spreading its 

 enamoured bosom to his ray," in some measure jus- 



* Moving plant. -j- Ply -trap. * Sensitive plant. 

 Berberry. Jj Orchis. 



