148 LEAVES. 



for others to determine. These are the leaves which 

 have already been mentioned, to prove that sensibility 

 is one of the properties of vegetable life. The Sensi- 

 tive plant, which shrinks from the slightest touch, is 

 nearly allied to several others which possess similar 

 degrees of this extraordinary power. The leaves of 

 the Fly-trap Dioncea muscipula, Fig. 53, exhibit no 

 marks of sensibility until the unfortunate fly ventures 

 to light on its surface, when it instantly closes and con- 

 fines the insect prisoner, as long as he continues to 

 struggle for escape. On the banks of the Ganges is 

 found a plant exhibiting such powers as to excite the 

 astonishment of every beholder. It is the Hedysarum 

 gyrajis or the Moving plant of India. If as he passes 

 by the playful Indian impedes its motion, no sooner 

 does it regain its liberty than its operations are renew- 

 ed with increased activity, as if it were necessary to 

 redeem the time which had been lost. I have seen this 

 plant in a green-house, and though no breath of air 

 disturbed the peace of its companions, its winged 

 leaves disdained to rest, but exhibited the most aston- 

 ishing example of industry I ever saw. 



The degree of vapour in the atmosphere has a pow- 

 erful effect upon the leaves of some plants, so that they 

 indicate with almost unerring certainty the approach of 

 rain. We are yet on the threshhold of discovery. 

 When we shall have advanced a few steps farther, those 

 plants which now appear to have been formed in vain, 

 will display their useful qualities, they will enable the 

 physician to combat disease, and the traveller to avoid 

 the impending storm. 



The leaf of Sarracenia* Fig.54 presents one of those 



* The Sarracenia purpurea frequently named Adam's Cup, or 



