20 INTRODUCTION. 



by this clammy liquid, and then the leaf closes, and holds 

 it fast till it dies. 



Mrs. B. The Dionea mascipula affords another exam- 

 ple of the same kind : it grows in the marshes of South 

 Carolina. Its irritability is so great, that an insect which 

 settles on it is generally crushed to death by the collaps- 

 ing of the two sides of the leaf, which, like that of the 

 Drosera, is armed with bristles. 



Caroline. But all plants are endued with some degree 

 of irritability, if you will not admit of sensibility ; for we 

 know that, in general, their leaves turn towards the light, 

 and when growing in a room, they spread out their 

 branches towards the windows, as if they were sensible 

 of the benefits they derived from light and air. 



Mrs. B. Light and air conduce to their well-being, 

 and they are so wisely constructed by Providence as to 

 seek them ; but it is independently of all choice or prefer- 

 ence. We must consider plants as beings in which the 

 principle of life is reduced to its state of greatest simpli- 

 city. As we advance in the scale of creation, we find 

 that the lowest animals are directed by instinct ; intelli- 

 gence increases as we approach towards man, who is 

 guided by reason : but the vegetable world is influenced 

 merely by physical causes, which derive their energy from 

 the principle of life. 



Emily. But since plants are so inferior in the scale 

 of existence, why is their form so much more delicate 

 and beautifully varied than that of animals ? Is it not 

 singular that Nature should be most solicitious for the ap- 

 pearance of her simplest works ? 



Mrs. B. The most curious details of the structure of 

 a plant are visible in its outward form ; whilst those of 

 the animal economy are concealed in the anatomical 

 structure of the internal parts. The organs of plants are 

 chiefly external, and are ornamental at the same time that 

 they perform the several functions for which they were 

 formed. 



45. Is any other example of the same kind mentioned 1 ? 46. What 

 is if? 47. What does Caroline say of the branches of plants growing 

 in a room 1 ? 48. What does Mrs. B. say in reply 1 ? 49. How is 

 the principle of life in plants to be considered'? 50. How is the case 

 varied as we advance in the scale of creation'? 51. What question is 

 proposed by Emily in relation to a seeming inconsistency in Nature! 

 52 What is Mrs. B.'s reply! 



