214 MARSH PLANTS 



impression that honey is to be obtained there gratis. 

 If the insect is a small one, it becomes firmly glued to 

 the surface of the leaf by mucilage secreted by the 

 glands. Somewhat later, another substance, a 

 digestive fluid, known scientifically as a ferment, is 

 also secreted by the part of the leaf with which the 

 insect is in contact. The ferment has the power of 

 reducing to a liquid state and digesting the insect, all 

 except the indestructible chitinous investment of the 

 body. Finally, the products are absorbed by the leaf 

 itself, and go towards its food-supply. The chitinous 

 investment of the insect remains attached until the 

 mucilage disappears, and it is then blown away by 

 the wind, or washed away by rain, and the trap for 

 fresh insects is set again. 



Such is, briefly, one of the most interesting of 

 phenomena among the Higher Plants. The insecti- 

 vorous habit, though not rare, is infrequent in the 

 vegetable kingdom. Examples occur in the case of 

 our British Sundews {Drosera) and Bladderworts 

 (Utricularia), some of which are also found in Lowland 

 Switzerland. Extreme or highly evolved adaptations 

 for a similar purpose are to be seen in the curious 

 tropical Pitcher plants (Nepenthes), commonly 

 cultivated in our greenhouses. Those who may be 

 interested to pursue this subject further should read 

 Charles Darwin's "Insectivorous Plants," which 

 contains a whole chapter devoted to the Butterworts. 



In this connection, it may be worth while to call 

 attention to some further points, discussed by Darwin, 



