On Flffwers and Insects. 



117 



increased, and they literally digest their prey. It 

 has been recently shown that plants supplied with 

 insects grow more vigorously than those not so 

 fed. If, on the other hand, a small stone, or any 

 other substance which contains no nourishment, 

 be placed on the leaf, though the hairs at first 

 close over it, they soon open again. It is very 



Fig. 25. COMMON SUNDEW (Drosera rotundifolia). 



curious that while the glands are so sensitive that 

 an object weighing only y-^j-j^th of a grain placed 

 on them is sufficient to cause motion, yet they are 

 "insensible to the weight and repeated blows of 

 drops" of even heavy rain. 



6. The Sundew, however, is not our only English 

 insectivorous plant. In the Butterwort, which fre- 



