THE VEGETABLE KINGDOM. 441 



CHAPTER IX. 



THE MOVEMENTS OF PLANTS. 



LIKE animals, plants are endowed with the power of 

 movement. The slightest observation shows this, as it does 

 their sensibility ; but some of our savants refuse to believe 

 it as obstinately as men opposed the first demonstrations of 

 the rotation of the earth. In vain is it shown that plants 

 move just like the seconds-hand of a watch ; that they con- 

 stantly change their position in order to sleep or protect 

 themselves from injury. Forasmuch as the old doctrine 

 taught that they are insensible and deprived of movement, 

 some timid minds do not wish to emancipate themselves 

 from it. 



Yet the movements of plants are susceptible of positive 

 proof, only we cannot discover the acting forces. But do 

 we know more about them in the most degraded of the 

 animal kingdom ? Certainly not. 



De Candolle and Tiedernann, trampling under foot purely 

 theoretical views, rightly admitted the mobility of plants. 

 The latter physiologist justly observes that it is not neces- 

 sary for the performance of this act that they should possess 

 fibres analogous to our muscles, and that the Medusae and 

 Infusoria move perfectly well without our being able to 

 discern anything of the kind in them. 



The movements of plants are spontaneous or accidental. 

 In the one case we see them operate by the instinctive im- 

 pulse of vegetable life ; in the other the plant only with- 

 draws itself from injury when it is irritated. 



