AUGUST. 



131 



H. Dr Darwin says, naturalists never 

 have explained the immediate cause. 



31. At the approach of night, how curious- 

 ly the leaves meet and close together, as 

 though asleep. 



H. And not only at night, but at all hours 

 of the day, the least touch, or concussion of 

 air produces the same effect ; and if the leaf 

 stems are touched, as though hung with 

 hinges on the main stem, they instantly drop; 

 presently recovering and resuming their for- 

 mer position ; so that a person would be in- 

 duced to think they were really endowed with 

 the sense of feeling. 



M. I have noticed when it was very hot, 

 the plant was most irritable — and when quite 

 cold, very slightly so. 



H. Every change of weather seems to af- 

 fect it ; so that it may justly be esteemed one 

 of the most w onderful plants. It is said that a 



