10 SENSIBILITY OF PLANTS. 



gesting them, and they have nothing which resembles a stomach ; 

 by the act of respiration, they possess themselves of the carbonic 

 acid of the air, and exhale the oxygen. 



7. We have said that vegetables are destitute of the faculty of 

 sensation, and the faculty of performing voluntary motion : this 

 is very evident in an immense majority of instances ; but 

 there are some plants which, at first sight, seem to form an ex- 

 ception to this rule. For example, the branches and leaves of 

 all plants are directed to that side from which they receive the 

 light and air. Certain plants on the approach of night, or the 

 morning dawn, close their leaves or flowers : and there are some 

 that contract themselves in this manner when they are touched 

 by any foreign body. The small shrub called the Sensitive 

 Plant exhibits this phenomenon in a very remarkable manner : 

 and a plant of certain 

 Carolina marshes, Venus's 

 Fly-trap, Dionma mus~ 

 cipula (jig. 1) performs 

 these motions most singu- 

 larly ; the leaves, which 

 are formed of two lobes, 

 are so irritable that they 

 close on the slightest touch ; 

 when an insect alights 

 upon the internal face of 

 one of them, the two lobes 

 immediately approximate 

 each other, and the ani- 

 mal, caught upon the 

 thorns with which these 

 lobes are armed, dies in 

 this species of natural 

 snare. The Sundew, 

 Drosera, the white flow- 

 ers of which often deck 

 the pools in France, are 

 somewhat analogous, for 



the hairs which fringe Fi S- L VENUS'S FLY-TRAP. 



their broad round leaves, lie down the moment they are irritated 

 by the contact of a foreign body. 



8. But these phenomena differ essentially from the voluntary 

 movements of animals ; there is no proof that the plants we have 



7. Do plants feel ? Are they capable of voluntary motion ? 



8. Is there any positive proof that vegetables feel, or move of their own 

 will? 



