256 FREAKS OF PLANT LIFE. 



" Any one who had never observed continuously 

 a sleeping plant," he says, " would naturally suppose 

 that the leaves moved only in the evening when going 

 to sleep, and in the morning when awaking ; but he 

 would be quite mistaken, for we have found no 

 exception to the rule that leaves which sleep continue 

 to move during the whole twenty-four hours ; they 

 move, however, more quickly when going to sleep, 

 and when awaking, than at other times. That they 

 are not stationary during the day has been de- 

 monstrated. It is troublesome to observe the move- 

 ments of leaves in the middle of the night, but this 

 was done in a few cases ; and tracings were made 

 during the early part of the night of the movements 

 in the case of several plants, 1 and the leaves after 

 they had gone to sleep were found to be in constant 

 movement. When, however, opposite leaflets come 

 into close contact with one another, or with the stem 

 at night, they are, as we believe, mechanically 

 prevented from moving, but this point was not 

 sufficiently investigated." • 



It is very certain that the more, and the closer, the 

 growth of plants is investigated, the more evident 

 does it become that there is a continual motion of 

 some kind going on, and that a state of life is a state 



1 In Oxalis, Amphicarjxza, two species oi Erythrina, Cassia, 

 Passiflora, Euphorbia, and Marsilea. 



2 Darwin, " Movements of Plants," p. 403. 



