228 THE STORY OF PLANT LIFE 



The longest tentacles are the most sensitive. But, if 

 one tentacle only is sensitive to contact, the rest 

 soon move in response, after a few minutes, making 

 an angle of ninety degrees in the movement. The 

 position of the object is also discerned, if one may 

 use such a word ; and if, in the centre, the tentacles 

 close over it, and if there is more than one object, 

 they group themselves accordingly. 



The entire leaf also exhibits movement, becoming 

 hollow above. An insect caught at the margin is 

 gradually brought into the centre. 



It takes about two days for a small insect to 

 become absorbed and finally dissolved by the acid 

 and pepsin ; the hard parts being of course un- 

 touched. Not only small insects, but larger types, 

 such as beetles and butterflies, share the same fate, 

 and quite a collection of different types may be 

 found on a leaf. Not only are the tentacles sensitive 

 to contact, but even parts of the leaf surface, at a 

 distance. This action is comparable with the 

 nervous system in animals. The cell-contents 

 exhibit aggregation, and the transmission of the 

 stimulus can be observed by the character of the 

 liquid in the vacuoles. After the insect has been 

 " digested," the tentacles resume their former 

 position, ready for the next victim. 



The Sundew is abundant in all parts of the British 

 Isles where there are bogs or moors, but these are, 

 owing to drainage, etc., becoming much less numerous 

 than they were. 



