INTRODUCTION. 19 



tion in the leaves which either shrunk or curled them- 

 selves up ; and, after exhibiting various symptoms of ir- 

 ritability during a short time, became flaccid, and the 

 plant in the course of a few hours died. 



Emily. I should have been curious to have seen an ex- 

 periment of this nature tried on the sensitive plant. 



Mrs. B. It was done. Two or three drops of prussic 

 acid, which, you know is a most powerful poison, were 

 poured upon a sensitive plant: the leaflets closed and 

 opened again at the end of a quarter of an hour ; but they 

 did not regain their sensitiveness for at least six or eight 

 hours. When we see plants thus acted upon by vegeta- 

 ble poisons, which are known to be incapable of destroy- 

 ing the animal fibre, or of injuring the frame but through 

 the medium of the nerves, we may be led to suppose, that 

 certain organs may exist in plants with which we are to- 

 tally unacquainted, and which bear some analogy to the 

 nervous system in animals. 



It is certain that plants possess the power of irritability 

 or contractibility ; for it is by alternate contractions and 

 dilitations of the vessels that they propel the juices which 

 rise within them. Here is a slip of elder: when I cut it 

 in two, the fluid continues oozing from both of the sepa- 

 rated parts ; were there no action going on within the 

 stem, only a single drop would flow out at each orifice. 

 There are some flowers, such as those of the Barberry, 

 whose stamens will bend and fold over the pistil, if the 

 latter be pricked with a needle ; and there is one instance 

 of a plant whose leaves move without any assignable 

 cause : this is the Hedysarum gyrans, which grows only 

 on the banks of the Ganges ; it has three leaflets on each 

 footstalk, all of which are in constant irregular motion. 



Emily. I recollect seeing a plant called Sundew, 

 (Drosera,) the leaves of which, near the root, are cover- 

 ed with bristles bedewed with a sticky juice. If a fly set- 

 tles on the upper surface of the leaf, it is at first detained 



37. What was the effect of them! 38. On the sensitive plant 

 what experiment was made! 39. What does Mrs. B. in view of these 

 experiments, think we may be led to suppose! 40. How are the 

 juices in plants made to rise! 41. What experiment is made with 

 the slip of elder! 42. What is said of the Barberry and some other 

 flowers of a similar description! 43. And of Hedysarum gyransf 

 44. What account does Emily give of a plant called Sundew? 



